Contact Dermatitis Part One

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Contact Dermatitis Part One

• Boris Ioffe, D.O., Pharm.D.
• 08-14-06

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Irritant contact dermatitis (ICD)

• Accounts for approximately 80 of all contact
  dermatitis
• ICD is the result of a local toxic effect when
  the skin comes in contact with irritant chemicals
  such as soaps, solvents, acids, or alkalis

• This 37-year-old woman developed a contact
  irritant dermatitis from obsessive-compulsive
  hand washing 20-30 times a day. www.drmatlas.org

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Introduction to Irritant Contact Dermatitis

• ICD is a cutaneous inflammation resulting from a
  direct cytotoxic effect of a chemical or physical
  agent
• Constitutes nearly 80 of occupational contact
  dermatitis (OCD)
• OCD is a matter of public health importance,
  contributing to combined direct and indirect
  annual costs (in the USA) of up to 1 billion
  when accounting for medical costs, workers
  compensation, and lost time from work

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Epidemiology of ICD

• The US Bureau of Labor Statistics data show that
  occupational skin diseases accounted for 10 to
  15 of all occupational illnesses
• High-risk occupations with frequent irritant
  exposure in caterers, furniture industry workers,
  hospital workers, hairdressers, chemical industry
  workers, dry cleaners, metal workers, florists,
  and warehouse workers

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Epidemiology of ICD

• Clinical manifestations of ICD are determined by
• Properties of the irritating substance
• Host factors
• Environmental factors including concentration,
  mechanical pressure, temperature, humidity, pH,
  and duration of contact
• Cold alone may also reduce the plasticity of the
  horny layer, with consequent cracking of the
  stratum corneum
• Occlusion, excessive humidity, and maceration
  increase percutaneous absorption of water-soluble
  substances

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• Bilateral shoe irritant dermatitis resulting from
  chronic occlusive footwear

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Epidemiology of ICD

• Important predisposing characteristics of the
  individual include
• Age, race, sex, pre-existing skin disease,
  anatomic region exposed, and sebaceous activity
• Both infants and elderly are affected more by ICD
  because of their less robust epidermal layer
• Patients with darkly pigmented skin seem to be
  more resistant to irritant reactions
• Other skin disease such as active atopic
  dermatitis may predispose an individual to
  develop ICD
• The most commonly affected sites are exposed
  areas such as the hands and the face, with hand
  involvement in approximately 80 of patients and
  face involvement in 10

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Pathogenesis of ICD

• Denaturation of epidermal keratins
• Disruption of the permeability barrier
• Damage to cell membranes
• Direct cytotoxic effects

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Acute Irritant Contact Dermatitis

• Commonly seen in occupational accidents
• Irritant reaction reaches its peak quickly,
  within minutes to hours after exposure
• Symptoms include stinging, burning, and soreness
• Physical signs include erythema, edema, bullae,
  and possibly necrosis
• Lesions restricted to the area where the irritant
  or toxicant damaged the tissue
• Sharply demarcated borders and asymmetry pointing
  to an exogenous cause
• Most frequent irritants are acids and alkaline
  solutions

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Acute Delayed Irritant Contact Dermatitis

• Delayed inflammatory response characteristic of
  certain irritants such as anthralin, benzalkonium
  chloride, and ethylene oxide
• Visible inflammation is not seen until 8 to 24
  hours after exposure
• Symptoms are more frequently burning rather than
  pruritus
• Sensitivity to touch and water are elicited
• This form of ICD is commonly seen during
  diagnostic patch testing

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Irritant Reaction Irritant Contact Dermatitis

• Type of subclinical irritant dermatitis in
  individuals exposed to wet chemical environments
  such as hairdressers, caters, or metalworkers
• Characterized by scaling, redness, vesicles,
  pustules, and erosions
• Often begins under occlusive jewelry and then
  spreads over the fingers to the hands and
  forearms
• May simulate dyshidrotic dermatitis

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Cumulative Irritant Contact Dermatitis

• Consequence of multiple sub-threshold skin
  insults, without sufficient time between them for
  complete barrier function repair
• In contrast to acute ICD, the lesions of chronic
  ICD are less sharply demarcated
• Itching and pain due to fissures of
  hyperkeratotic skin are symptoms of chronic ICD
• Skin findings include lichenification,
  hyperkeratosis, xerosis, erythema, and vesicles

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Asteatotic Dermatitis

• Exsiccation eczematid ICD
• Seen mainly during the winter months in elderly
  individuals who frequently bath without
  remoisturizing
• Skin appears dry with ichthyosiform scale and
  patches of eczema craquele

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Traumatic Irritant Contact Dermatitis

• May develop after acute skin trauma, such as
  burns, lacerations, or acute ICD
• Patients should be asked if they have cleansed
  with strong soaps or detergents
• Characterized by eczematous lesions most commonly
  on the hands, that persist
• Healing is delayed with redness, infiltration,
  scale, and fissuring in the affected areas

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Pustular and Acneform Irritant Contact Dermatitis

• Result to certain irritants such as metals,
  croton oil, mineral oils, tars, greases, cutting
  and metal working fluids, and naphthalenes
• Should be considered in conditions in which
  folliculitis or acneform lesions develop in
  setting outside of typical acne
• Pustules are sterile and transient
• Milia may develop in response to occlusive
  clothing, adhesive tape, ultraviolet and infrared
  radiation

Chloracne. Note heavy involvement of
retroauricular skin with comedones and cysts
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Subjective or Sensory Irritant Contact Dermatitis

• Reports of stinging or burning in the absence of
  visible cutaneous signs of irritation
• Response to irritants such as lactic or sorbic
  acid

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Airborne Irritant Contact Dermatitis

• Develops on irritant-exposed skin of the face and
  periorbital regions
• Often simulates photoallergic reactions
• Involvement of the upper eyelids, philtrum, and
  submental regions help to differentiate from
  photoallergic reaction

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Frictional Irritant Contact Dermatitis

• Results from repeated low-grade frictional trauma
• Plays adjuvant role in ACD and ICD
• Characterized by hyperkeratosis, acanthosis, and
  lichenification, often progressing to hardening,
  thickening, and increased toughness

9 year old girl demonstrates a lichenified
hyperpigmented round plaque on the top of her
thumb produced by chronic thumbsucking.
www.dermatlas.org
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Pathology of ICD

• Variable mix of inflammation, necrosis of
  epidermal keratinocytes, and mild spongiosis
• Combination of an upper dermal perivascular
  infiltrate of lymphocytes with minimal extension
  of inflammatory cells into the overlying
  epidermis, and widely scattered necrotic
  keratinocytes is most typical picture
• True features of interface dermatitis are absent,
  and spongiosis should be focal or absent
• Over time additional histologic findings include
  acanthosis with mild hypergranulosis and
  hyperkeratosis

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Acids

• Inorganic and organic acids can be corrosive to
  the skin
• Cause epidermal damage via protein denaturation
  and cytotoxicity
• Symptoms include erythema, vesication, and
  necrosis
• Hydrofluoric and sulfuric acid can cause the most
  severe burns
• Hydrofluoric acid, used in the semiconductor
  industry, is able to penetrate intact skin with
  subsequent dissociation in deeper tissues and
  resultant liquefactive necrosis

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Acids

• Chromic acid causes ulcerations known as chrome
  holes and often perforates the nasal septum
• Chemical burns and irritant dermatitis from
  nitric acid can cause a distinctive yellow
  discoloration
• In general, organic acids are less irritating
  than inorganic acids
• Formic acid has the greatest corrosive potential
  of the organic acids

Examples of chrome holes www.cdc.gov/niosh/ocderm
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Alkalis

• Strong Alkalis include sodium, ammonium,
  potassium hydroxide, sodium and potassium
  carbonate, and calcium oxide
• Found in soaps, detergents, bleaches, ammonia
  preparations, lye, drain pipe cleaner, toilet
  bowl cleansers, and oven cleaner
• Often more painful and damaging than acids
• No vesicles, necrotic skin that appears dark
  brown then black, ultimately becomes hard, dry,
  and cracked
• Alkalis disrupt barrier lips and denature
  proteins with subsequent fatty acid
  saponification

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Alkalis

• Cement mixed with water can cause ulcerative
  damage due to alkalinity
• Changes appear 8 to 12 hours after exposure
• Chronic irritant cement dermatitis may also
  develop over months to years
• Can accompany allergic contact dermatitis

Hand dermatitis due to contact with cement
dermnetnz.org/dermatitis/chrome
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Metal Salts

• Include arsenic trioxide, beryllium compounds,
  calcium oxide, copper salts, inorganic mercury,
  thimerosal, and selenium
• Signs ranging from ulceration to folliculitis

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Solvents

• Act mainly by dissolving the intercellular lipid
  barrier of the epidermis
• Prolonged skin contact can result in severe burns
  and well as systemic toxicity
• Examples include turpentine, benzene, toluene,
  xylene, carbon tetrachloride, gasoline, and
  kerosene

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• Professional paint and crayon illustrator with
  bilateral palmar dermatitis secondary to repeated
  contact with paint solvents. Extensive patch
  testing excluded allergic contact dermatitis

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Detergents and Cleansers

• Include any surface active agent (surfactant)
  that concentrates at the oil-water interfaces and
  has both emulsifying and cleansing properties
• Found in skin cleansers, cosmetics, and household
  cleaning products
• Surfactants cause protein denaturation of the
  stratum corneum, impairing barrier function
• Anionic detergents such as alkyl sulfates and
  alkyl carboxylate salts are the most irritating

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Disinfectants

• Include, alcohols, aldehydes, phenolic compounds,
  halogenated compounds, surfactants, dyes,
  oxidizing agents, and mercury compounds
• Weak toxic agents that can cause chronic ICD

Practicing dentist with moderately severe
irritant hand dermatitis from chronic exposure to
disinfecting solutions and antiseptics. The
results of patch testing, latex challenge
testing, and RAST testing were negative.
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Plastics

• Three categories thermoplastics, thermosettings,
  elastomers
• Skin damage is attributed to monomer ingredients,
  hardeners, and stabilizers
• Final hardened plastic product is generally
  considered inert

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Food

• Agriculture, fishing, catering, and food
  processing
• Often work without gloves, in damp working
  conditions with frequent hand washing
• Mechanical, thermal, and climatic factors
• Nearly 100 of exposed persons in food handling
  and fishing professions may be affected by
  chronic irritant hand dermatitis

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Water

• Ubiquitous skin irritant
• Tropical immersion foot, seen during Vietnam War
• Hairdressers, hospital cleaners, cannery workers,
  bartenders
• Irritancy of water is exacerbated by occlusion

9 year old is an habitual hand washer who
develops a contact irritant dermatitis every
winter. At times she washes over 10 times a day.
www.dermatlas.org
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Fabric/man-made vitreous fibers

• Fibers larger than 3.5 um in diameter cause the
  highly pruritic contact dermatitis caused by
  fiberglass
• Erythematous papules with superimposed
  excoriations on neck and dorsal hands
• Wool and rough clothing cause dermatitis in
  atopic individuals

Fiberglass dermatitis www.cdc.gov/niosh/ocderm
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Differential Diagnosis

• Allergic and ICD, especially in chronic stage
  appear similar by clinical appearance, histology,
  and immunohistology
• Look identical with erythema, papules, xerosis,
  scaling, and lichenification with sharp borders
• ICD has remained a diagnosis of exclusion when
  dermatitis is not explained by positive patch
  test to a known allergen
• More frequent complaint of burning and stinging
  with ICD in contrast to pruritus in ACD

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Treatment

• Avoidance of causative irritants at home or in
  the workplace is the primary TX
• Engineering controls to reduce exposure in the
  workplace
• Shielding and personal protection such as gloves
  and special clothing
• Pre-exposure protection by protective creams,
  removal of irritants by mild cleaning agents, and
  enhancement of barrier function generation by
  emollients and moisturizers
• Emphasizing personal and occupational hygiene
• Establishing educational programs to increase
  awareness in the workplace

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TX Chemical Burns

• Initial tx irrigation with large volumes of
  water, if chemical is insoluble in water a soap
  solution may be used
• High pressure water to be avoided to prevent
  splashing
• 2.5 calcium gluconate gel used to tx
  hydroflouric acid burns, immediate application of
  a weak acid such as vinegar, lemon juice, or 0.5
  hydrochloric acid will lessen the effect of
  alkali burns
• Ulcerated areas should be managed with
  antibacterial creams or ointments to prevent
  secondary infection
• Frequent evaluation is required because ulcers
  may progress over several days
• Excision, debridement and/or grafting may speed
  healing
• Monitoring of blood, liver, and kidney function
  may be needed when exposed to chemicals with
  potential for systemic toxicity such as
  hydrofluoric acid, phenolic compounds, chromic
  acid, and gasoline

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Chronic ICD Treatment

• Tx goal is to restore normal epidermal barrier
  function
• Topical corticosteroids frequently used
• Systemic corticosteroids although helpful in
  reducing inflammation, are not useful in
  treatment of chronic ICD unless offending
  contactants are avoided
• PUVA and Grenz ray considered for chronic
  dermatitis that does not respond to other tx
• Hyperkeratotic palmoplantar dermatitis from
  frictional or chronic ICD may benefit from the
  adjunctive use of systemic retinoids such as
  acitretin

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Allergic contact dermatitis (ACD)

• ACD accounts for approximately 20 of all contact
  dermatitis
• ACD is a type IV, delayed or cell-mediated immune
  reaction that is elicited when the skin comes in
  contact with a chemical to which an individual
  has been previously sensitized
• Synonyms include contact dermatitis and contact
  eczema

• Allergic contact dermatitis. Linear streaks seen
  with ACD to poison ivy.

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ACD

• Key Features
• ACD is a pruritic, eczematous reaction
• Acute ACD and many cases of chronic ACD are well
  demarcated and located to the site of contact
  with the allergen
• Prototypic reactions are ACD due to poison ivy
  and nickel
• Patch testing remains the gold standard for
  accurate and consistent diagnosis

This healthy adolescent developed an intensely
pruritic vesiculobullous allergic contact
dermatitis from hair dye. Dermatlas.org
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• Classic picture of ACD is a well-demarcated
  erythematous vesicular and/or scaly patch or
  plaque with well defined margins corresponding to
  the area of contact

• Chronic allergic contact dermatitis leading to
  hand dermatitis. This golfer wore one leather
  glove and had positive patch tests to potassium
  dichromate and a piece of his glove. Courtesy of
  Kalman Watsky, M.D.

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• Allergic contact dermatitis to leather shoes.
  Note the correspondence to sites of exposure.
  Courtesy of Yale Residents Slide Collection.

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• Because ICD and ACD are not always discernable
  clinically, patch testing is required to help
  identify an allergen or exclude an allergy to a
  suspected allergen.

• Allergic contact dermatitis. Chronic hand
  dermatitis due to ACD to mercaptobenzothiazole
  found in rubber gloves

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Epidemiology of ACD

• Affects the old and young, individuals of all
  races, and both sexes
• Differences in genders usually based on exposure
  patterns, such as nickel allergy being seen more
  frequently in women, presumably due to greater
  exposure to jewelry
• Occupations and avocations play an important role
• Allergens differ from region to region, e.g.
  preservatives used in personal care products can
  vary based on government legislation

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Pathogenesis of ACD

• ACD is a type IV hypersensitivity response
• Requires prior sensitization to the chemical in
  question
• Subsequent re-exposure of individual leads to
  allergen being presented to a primed T-cell
  milieu leading to release of numerous cytokines
  and chemotactic factors leading to the clinical
  picture of eczema
• Once sensitized a low concentration of causative
  chemical elicits a response

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• Induction of contact hypersensitivity.
  Application of contact allergens (Ag) induces the
  release of cytokines by keratinocytes, Langerhans
  cells and other cells within the skin. These
  cytokines in turn activate Langerhans cells which
  uptake the antigen and emigrate into the regional
  lymph nodes. During this process, the Langerhans
  cells mature into dendritic cells. In addition,
  the antigen is processed, re-expressed on the
  surface and finally presented to naïve T cells in
  the regional lymph node. Upon appropriate antigen
  presentation, T cells bearing the appropriate T
  cell receptor clonally expand and become effector
  T cells. These alter their migratory behavior due
  to the expression of specific surface molecules
  like CLA. Effector T cells recirculate into the
  periphery where they may later meet the antigen
  again. Ag, antigen KC, keratinocyte.

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• Elicitation of contact hypersensitivity.
  Application of contact allergens (Ag) into a
  sensitized individual causes the release of
  cytokines by keratinocytes and Langerhans cells.
  These cytokines induce the expression of adhesion
  molecules and activation of endothelial cells
  which ultimately attracts leukocytes to the site
  of antigen application. Among these cells, T
  effector cells are present which are now
  activated upon antigen presentation either by
  resident cells or by infiltrating Langerhans
  cells. Antigen-specific T cell activation again
  induces the release of cytokines by T cells. This
  causes the attraction of other inflammatory cells
  including granulocytes and macrophages which
  ultimately cause the clinical manifestation of
  contact dermatitis. Ag, antigen DDC, dermal
  dendritic cell KC, keratinocyte CLA, cutaneous
  lymphocyte antigen.

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Clinical features of ACD

• Acute blistering and weeping
• Chronic lichenified and scaly plaques
• Patchy and diffuse distributions may be seen with
  body washes and shampoos

• Acute bullous allergic contact dermatitis due to
  poison ivy. This distribution is seen in patients
  who wear gloves. Courtesy of Yale Residents Slide
  Collection

• Chronic allergic contact dermatitis due to
  glutaraldehyde. The patient was an optometrist

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Pathology of ACD

• ACD is the prototype of spongiotic dermatitis
• Acute stage variable degree of spongiosis with
  mixed dermal inflammatory infiltrate containing
  lymphocytes, histiocytes, and variable numbers of
  eosinophils
• Moderate to severe reactions show intraepidermal
  vesiculation
• Subacute to chronic stages have epidermal
  hyperplasia, often psoriasiform

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DDX of ACD

• Includes many forms of dermatitis ICD, atopic
  dermatitis, stasis dermatitis, and seborrheic
  dermatitis, as well as the erythematous form of
  rosacea
• Hand and foot ACD need to be distinguished from
  psoriasis and tinea
• Widespread disease needs to be differentiated
  from other causes of erythoderma, Sezary syndrome

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Patch Testing

• Simple office procedure upon which the diagnosis
  of ACD often rests
• Although the procedure is simple, deciding when
  and what to test for requires training and
  experience
• Patch testing is underutilized
• Only 50 of all residency programs in USA have a
  patch
• test center
• Past surveys show 27 of the responders did no
  patch testing

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Patch Testing

• TRUE Test
• Other panels include North American Contact
  Dermatitis Group (NACDG) Screening Series, and
  the European Standard Series
• Other panels are unique to specific occupations
  such as hairdressing tray, dental tray, and
  florist tray

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True Test

• Preimpregnated test that screens for 23 allergens
• Extending testing beyond these 23 allergens has
  shown to be more beneficial
• In three studies, extended testing detected
  37-76 more positive reactions, and 47.3 of
  patients had positive reactions only to
  non-screening allergens
• Additional allergens come in multiuse syringes

Application of TRUE test. www.truetest.com

• Allergens contained within syringes being placed
  by nurse into Finn chambers

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Pre-Patch Testing Questions

• Exposures both at work and home to understand
  mechanics of the work environment, Materials
  Safety Data Sheets (MSDS) can be helpful for
  workplace exposures
• Effect of vacations and time away form work or
  home should be ascertained
• All personal care products should be inventoried
• All hobbies should be explored

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Patch Testing

• Chemicals brought in by patients should not be
  tested blindly, physician should be aware of the
  chemical ingredients because severe burns or
  ulceration may occur
• Leave on personal care products such as
  moisturizers and make-up may be tested as is
• Rinse off products such as soaps or shampoos
  need to be diluted prior to patch testing

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Patch Testing

• Most common site is the upper back
• Patients should not have a sunburn in test area,
  and should not apply topical corticosteroids to
  the patch test sites for 7 days prior to test
• Systemic corticosteroids should be avoided for 1
  month prior to testing
• Patches are applied to back and reinforced with
  Scanpor tape, patient instructed to keep back dry
  and patches secured until second visit at 48 hours

• Fixing allergens to patient's back using Scanpor
  tape.

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Patch Testing

• When the patient returns in 48 hours the patches
  need to be inspected to ensure that the testing
  technique is adequate
• As patches are removed their sites of
  application should be marked in order to
  identify the locations of particular allergens

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Patch Test Scoring

• A positive patch test reaction to nickel. This is
  an example of a 3 reaction

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Patch Testing

• Patient again asked to keep back dry until second
  reading, done from 72 hours to 1 week after the
  initial application of the patches
• This delayed reading is necessary due to patch
  test responses to some allergens such as gold
  having a delayed reaction

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Repeat Open Application Test (ROAT)

• Poor mans patch test
• Patient applies the product in question to the
  same location (where there is not dermatitis),
  e.g. antecubital fossa, BID for 1-2 weeks
• If dermatitis develops, it can be concluded that
  the patient is reacting to the product
• Downside to this approach is that individual
  problem ingredients are not identified

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Treatment and Patient Education

• Once allergens are positively identified, patient
  should be given written information on all of
  these chemicals
• Patient should be instructed on how to read
  labels on old or new products to avoid future
  exposure

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Treatment of ACD

• Involves identification of causative allergens
• Clear the dermatitis with topical, or if
  necessary systemic corticosteroids
• Complete and prolonged clearing can take up to 6
  weeks or more, even when allergens are being
  avoided

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Nickel

• Most common allergen tested by the NACDG, with
  14 of patients reacting to it
• Relevance has been estimated to be 50
• Commonly used in jewelry, buckles, snaps, and
  other metal-containing objects
• High rate of sensitivity attributed to ear
  piercing
• Dimethylglyoxime test to determine if a
  particular item contains nickel
• Individuals with nickel allergy should avoid
  custom jewelry, and can usually wear stainless
  steel or gold

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Nickel Dermatitis

• Common presentations are dermatitis on the ears,
  under a necklace or a watch back, or on the
  mid-abdomen caused by a belt buckle, zipper, or
  snap
• Eyelid dermatitis from metal eyelash curlers can
  be seen

• Photos from dermatlas.org

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Neomycin Sulfate

• Most commonly used topical antibiotic
• Most common sensitizer among topical antibiotics
• Found in many OTC preparations bacterial
  ointments, hemorrhoid creams, and otic and
  opthalmic preparations
• Frequently used with other antibacterial agents,
  such as bacitracin and polymyxin, as well as
  corticosteroids
• Co-reactivity is commonly seen with neomycin and
  bacitracin

13 year old boy developed an itchy allergic
contact dermatitis from a topical antibiotic.
www.dermatlas.org
69
Balsam of Peru

• Naturally occurring fragrance material
• Prior to introduction of fragrance mix in the
  1970s, balsam of Peru was used to screen for
  fragrance allergy
• Capable of identifying 50 of those allergic to
  fragrance
• Seen in those with allergies to spices, in
  particular cloves, Jamaicin pepper, and cinnamon
• Patients with a positive reaction need to avoid
  fragrances, occasionally spices, and other
  sources such as colas, tobacco, wines, and
  vermouth

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Fragrance Mix

• Contains eight different components cinnamic
  etoh, cinnamic aldehyde, hydroxycitronellal,
  isoeugenol, eugenol, oak moss absolute,
  alpha-amyl cinnamic aldehyde, and geraniol
• Detects 70-80 of fragrance allergies
• Patients need to read product labels and avoid
  anything that lists a fragrance, is labeled
  unscented, or has an obvious scent
• Patients need to look for fragrance-free
  products

• ACD to fragrance found in cologne. A Patient with
  ACD to fragrance found in his cologne. B Patient
  after avoidance of fragrances and his cologne.

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Thimerosal

• Thimerosal is a combination of thiosalicylic acid
  and ethylmercuric chloride, and is used as a
  preservative
• Most sensitization may be due to its use as a
  preservative in vaccines
• Other exposures include contact lens solution,
  otic and opthalmic solutions, antiseptics, and
  cosmetics
• Positive reactions are common, relevance is low
  and therefore routine testing to this allergen
  should be reconsidered

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Gold

• NACDG found a positive rate of 9.5
• NACDC found 90 of gold-allergic patients were
  women, and there was a higher rate of nickel
  (33.5) and cobalt allergy (18) in this group
• Most common clinical picture is hand, facial, or
  eyelid dermatitis
• Systemic reactions to gold in patients whom it
  was used to tx RA, SLE, or pemphigus.
• Cutaneous findings of lichen planus-like
  reactions to pityriasis rosea-like reactions and
  papular eruptions with systemic reactions

73
Formaldehyde

• Is a ubiquitous, colorless gas found in the
  workplace, cosmetics, medications, textiles,
  paints, cigarette smoke, paper, and formaldehyde
  resins in plastic bottles
• Commonly seen in association with
  formaldehyde-releasing presevatives, such as
  quarternuim-15 imidazolidinyl urea, diazolidinyl
  urea, DMDM hydantoin, 2-bromo-2-nitropropane-1-3,d
  iol, and tris(hydroxymethyl)nitromethane
• ICD is most common, ACD, contact urticaria, and
  mucous membrane irritation can occur
• Textile dermatitis due to formaldehyde resins in
  wash-and-wear and wrinkle resistant clothes
• Another source of formaldehyde is
  formaldehyde-free products that are packaged in
  containers coated with formaldehyde resins
• So widespread that avoidance is difficult and
  clinical relevance should be determined

74
Quaternium-15

• Preservative that is an effective biocide against
  Pseudomonas, as well as other bacteria and fungi
• Most common preservative to cause ACD
• Found in shampoos, moisturizers, conditioners,
  and soaps
• 80 of those reacting to quarternium-15 are also
  formaldehyde sensitive

Hand dermatititis due toquaternium-15 in a
moisturiser dermnetnz.org/dermatitis/quaternium
75
Cobalt

• Metal that is used in association with other
  metals to add hardness and strength
• Frequently combined with nickel, chromium,
  molybdenum, and tungsten
• 80 of individuals with a cobalt sensitivity have
  a co-sensitivity to chromate (more common in men)
  or nickel (more common in women)
• Exposure through jewelry snaps, buttons, tools,
  cosmetics, hair dyes, joint replacements,
  ceramics, enamel, cement, paints , and resins

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Bacitracin

• Topical antibiotic with activity against
  Gram-positive bacteria and spirochetes
• Commonly used in combination with other
  antibiotics such as neomycin and with
  corticosteroids
• In addition to ACD, also rarely causes
  anaphylaxis and contact urticaria

Chronic ulcerations on the lower extremity are
particularly likely to develop allergic contact
dermatitis. This eruption resulted from
sensitization to bacitracin. www.worldallergy.org
77
Corticosteroids

• Have been shown to cause ACD in anywhere from
  0.2 to 5.98
• It is suspected that ACD to these agents is
  underdiagnosed, due to insufficient testing
• Clinical scenarios that should raise suspicion
  include chronic dermatitis, failure to clear
  with corticosteroids, and exacerbations of
  dermatitis after use of corticosteroids
• Tixocortol-21-pivalate and budesonide used for
  screening, with 91.3 of corticosteroid allergic
  reactions detected
• Complicates patch test interpretation, due to
  edge effect (first reading may have erythema only
  at the rim of the Finn chamber)

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Systemic Contact Dermatitis

• Systemic exposure to a chemical may result in a
  diffuse dermatitis
• Patient has had a prior contact allergy and then
  becomes exposed through a systemic route, such as
  injection, oral, intravenous, or intranasal
  administration
• One of most common examples is patient with
  ethylenediamine allergy and subsequent reaction
  to aminophylline

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Airborne Contact Dermatitis

• Airborne allergens result in several different
  reactions including ICD and ACD
• PhotoACD, photoICD, photoxicity, and photoallergy
  to systemic medications clinically resemble
  airborne contact dermatitis
• Ragweed dermatitis is a classic example
• Clinically, lichenified and dry skin located in
  the exposed portions of the skin face, V of the
  neck, arms and legs
• Most common causative agents are plants, natural
  resins, woods, plastics, rubbers, glues, metals,
  pharmaceutical chemicals, insecticides and
  pesticides

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55-year-old farm worker developed a chronic
allergic contact dermatitis to airborn allergens
(compositae).
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Anacardiacea Dermatitis

• Poison Ivy vine growing up a tree
  www.dermatlas.org

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Anacardiacea ACD

• Members of the Anacardiaceae cause more contact
  dermatitis that all other plant families combined
• Most allergenic members belong to the genus
  Toxicodendron, including poison ivy, poison oak,
  and poison sumac
• Tocicodendron leaves are compound, possessing
  three or more leaflets. Flowers and fruit arise
  in an axillary positions in the angle between the
  leaf and the twig from which it arises
• Black dots of urushiol often present on leaves
  and fruit

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Anacardiacae Allergens

• Urushiol derives its name form the Japanese word
  for the sap (kiurushi) of the Japanese lacquer
  tree
• Urushiol contains a mixture of catechols
  (1,2-dihydroxybenzenes) and resorcinols
  (1,3-dihydroxybenzenes)
• Urushiol self-melanizes on exposure to oxygen
• Avidly binds to skin but is readily degraded by
  water

• Poison Ivy www.dermatlas.org

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Clinical Features Anacardiacea Dermatitis

• Damage is generally required for plants to
  release urushiol
• In late fall plants release urushiol
  spontaneously
• Urushiol may be spread by contaminated clothing,
  dogs, cats, lacquered furniture, sawdust, and
  smoke
• Allergen-containing smoke can cause severe
  respiratory tract inflammation, severe
  dermatitis, and even temporary blindness

• www.dermatlas.org

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Clinical Features Anacardiacea Dermatitis

• After contact with urushiol, a sensitized person
  typically develops and pruritic , erythematous
  eruption within 2 days (4-96 hours) that peaks
  within 1-14 days
• Dermatitis may last up to 3 weeks after primary
  contact or within hours of secondary contact
• Streaks of erythema and edematous papules
  typically precede vesicles and bullae
• Although ACD is the most common cause of streaky,
  vesicular dermatitis, plants may cause this same
  picture by other means e.g. chemical irritant
  dermatitis, or the initial phase of
  phytodermatitis

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• Clinical manifestations of Anacardiaceae
  dermatitis. A Acute, streak-like edematous and
  erythematous dermatitis without vesicles after
  poison ivy brushed across the face. Courtesy of
  Fitzsimons Army Medical Center Dermatology slide
  teaching library. B Acute, streak-like vesicular
  dermatitis after poison ivy (Toxicodendron
  radicans) contact. Courtesy of Fitzsimons Army
  Medical Center Dermatology slide teaching
  library. C Widespread erythema and edema
  associated with intense pruritus after carrying
  logs of the poisonwood tree (Metopium toxiferum)
  of the family Anacardiaceae. D Black-spot
  poison ivy dermatitis note the black
  discoloration in the central portion of the
  edematous plaques due to plant resin.

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Clinical Features Anacardiacea Dermatitis

• Eruption progresses to new areas because of
  variability in antigen concentration and stratum
  corneum/epidermis thickness, not because of
  bullae fluid
• Over 70 of the US population reacts to poison
  ivy allergens after patch testing, but only 50
  react to plants in the field
• Only 15 atopic patients are sensitive to poison
  ivy
• Uncommonly, eruptions resemble erythema
  multiforme, measles, scarlatina, or urticaria
• Prolonged postinflammatory hyperpigmentation may
  occur in darkly pigmented individuals

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Treatment

• Entire body should be washed with copious amounts
  of water as soon as possible after exposure
• Soap may be used afterwards, but early use of
  soap may expand the area of resin on the body
• As mentioned before, urushiol is water
  degradable, After 10 minutes only 50 can be
  removed, after 15 minutes only 25 can be
  removed, after 30 minutes only 10 can be
  removed, and after 60 minutes none of it can be
  removed

www.dermatlas.org
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Treatment

• Weepy lesions are best treated with tepid baths,
  wet-to-dry soaks, or bland shake lotions
  (calamine)
• Stringent such as Burows solution (aluminum
  subacetate) works to cool and dry lesions when
  applied as a wet-to-dry dressing
• Topical antihistamines, anesthetics containing
  benzocaine, and antibiotics should be avoided to
  prevent sensitization

• www.dermatlas.org

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Treatment

• Most potent topical corticosteroids only help if
  applied during the earliest stages of the
  outbreak, when vesicles and blisters are not yet
  present
• Systemic steroids are effective when given at a
  dose of 1-2 mg/kg/day, slowly tapered over 2-3
  weeks
• Many patients are referred for a recurrence of
  their poison ivy dermatitis after completing a
  short, 6 day course of oral corticosteroids
• Oral antihistamines may decrease pruritus

• www.dermatlas.org