Atopic Dermatitis: Immunology and management

1
Atopic Dermatitis Immunology and management

• Dr Amal Kokandi
• (MBBCh, DDSc, MD)

2
ECZEMA

• Synonymous with dermatitis
• Large proportion of skin disease in developed
  world
• 10 of population at any one time
• 40 of population at some time

3
Features of eczema

• Itchy
• Erythematous
• Dry
• Flaky
• Oedematous
• Crusted
• Vesicles
• lichenified

4
Diagnosis

• Clinical
• No specific laboratory test
• Family history of atopy is helpful
• Criteria for research studies Hanifin Rajka
  (1980), United Kingdom Party Criteria (1994)

5
Severity

• Clinical Extent, sleep disturbance, Itching,
  Quality of life.
• ADASI (diagramatic), SASSAD, SIS (intensity
  scoring), etc
• Biophysical methods
• Eosinophils
• IgE (80)
• Immunological markers (sIL-2R, ECP, sCD23,
  sICAM-1, sELAM-1, sVCAM-1, E selectin, MBP..)

6
Atopic eczema

• Endogenous
• Atopic i.e asthma, hay fever
• 5 of population
• 10-15 of all children affected at some time

7
Exacerbating factors

• Detergents
• Infection
• Teething
• Stress
• Cat and dog fur
• ???? House dust mite
• ???? Food allergen

8
Clinical features

• Itchy erythematous scaly patches
• Flexures of knees and elbows
• Neck
• Face in infants
• Exaggerated skin markings
• Lichenification
• Nail pitted ridged

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
complications

• Bacterial infection
• Viral infections warts, molluscum, herpes
• Keratoconjunctivitis
• Retarded growth

15
Pathogenesis

• Not fully understood
• Genetics
• Environmental factors Irritants, aeroallergens,
  seasonal, hormonal and stress
• Microbial organisms (Staph Aureus, Malassezia,
  skin fungi.) and superantigens
• Modified skin barrier function
• Deficiency in innate immune system and toll like
  receptors
• Specific immunity (biphasic Th1 Th2)

16
Genetics of atopic eczema

• 77 15 concordance in mono- dizygotic twins.
• significant linkage on chromosomes 1q21, 3q21 ,
  3q24-22 , 3p26-24 17q25
• polymorphisms in genes important for epidermal
  differentiation, inflammation (IL-4, IL-12,
  Fillagrin.)

17
investigations

• Clinical
• ??IgE
• ??RAST

18
Prognosis

• Most grow out of it!
• 15 may come back often very mildly

19
Treatment

• Patient education
• Emollients
• Avoid triggering factors irritants especially
  soap
• Topical steroids
• Treat infections
• Sedating antihistamines
• Second line agents Calcineurin inhibitors, UV
  therapy and systemic therapy
• Immunotherapy Desensitization

20
creams

• Cosmetically more acceptable
• Water based
• Contain preservatives
• Soap substitutes

21
ointments

• Oil based
• Dont contain preservative
• Feel greasy
• Good for hydrating

22
Topical steroids potency (European)

• Mild hydrocortisone
• Moderate eumovate
• Potent betnovate
• Very potent dermovate

23
Topical steroid potency (American)

• Class1 (superpotent)
• Class2 (potent)
• Class3 (potent)
• Class4 (midstrength)
• Class5 (midstrength)
• Class6 (mild)
• Class7 (least potent)

24
FTU

• Finger tip unit
• Helps to give estimation of topical steroid
  amount used
• To avoid over and under use of steroid

25
FTU
26
Finger tip unit

• 2 FTU nearly 1 gram
• Enough for twice size of adult hand
• A hand and fingers (front and back) 1FTU
• A foot (all over) 2FTU
• Front of chest and abdomen 7FTU
• Back and buttocks 7FTU
• Face and neck 2.5 FTU
• An entire arm and hand 4 FTU
• An entire leg and foot 8 FTU

27
Special considerations

• Face
• Intertriginous areas
• Children
• Effect of occlusion
• infections and combination formulas (with
  antibiotics and antifungals)

28
Topical steroid side effects

• Perioral dermatitis and rosacea
• Tachyphylaxis steroid addiction
• Infections (tinea incognito, herpes simplex,
  pityriasis versicolor, scabies)
• Adrenal suppression
• Glucoma and cataract
• Angina bullosa purpura (hard palate)

29
Topical steroid side effects

• Telangiectasia, purpura, epidermal, dermal and
  subcutaneous atrophy, striae, psuedoscars
• Folliculitis
• Allergic reactions
• Hypopigmentation
• Hypertrichosis
• Delayed wound healing
• Alteration in skin elasticity mechanical
  properties
• tinea incognito

30
(No Transcript)