Allergy: anaphylactic shock, nettle rash, Quincke

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Allergy anaphylactic shock, nettle rash,
Quinckes edema. Toxicallergic affections of skin
and mucosa. Etiology, pathogenesis. Diagnostics.
Clinical picture. Complications. Principles of
treatment. The role of a doctor-dentist in
early diagnostics and prophylaxis.

• Khabarova N.A.

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• Allergic reactions are sensitivities to
  substances called allergens that come into
  contact with the skin, nose, eyes, respiratory
  tract, and gastrointestinal tract. They can
  be breathed into the lungs, swallowed, or
  injected. Allergic reactions are common. The
  immune response that causes an allergic reaction
  is similar to the response that causes hay fever.
  Most reactions happen soon after contact with an
  allergen.
• Many allergic reactions are mild, while others
  can be severe and life-threatening. They can be
  confined to a small area of the body, or they may
  affect the entire body. The most severe form is
  called anaphylaxis or anaphylactic shock.

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• Causes
• Common allergens include
• Animal dander
• Bee stings or stings from other insects
• Foods, especially nuts, fish, and shellfish
• Insect bites
• Medications
• Plants
• Pollens

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Trends in age and sex standardised admission
rates for anaphylaxis, angio-oedema, food
allergy, and urticaria, with rate ratios (RR) and
95 confidence intervals, England 1990-2001
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Control of the immune system by the
hypothalamo-pituitary axis during an antigen
attack.
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Formation of sensitised lymphocytes, lymphokines
and antibodies. B-lymphocytes are involved in
acquired, humoral immunity, and T-lymphocytes in
congenital, cellular immunity.
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• Anaphylaxis is a severe, systemic allergic
  reaction
• multisystem involvement, including the skin,
  airway, vascular system, and GI
• Severe cases may result in complete obstruction
  of the airway, cardiovascular collapse, and death
• Anaphylactoid or pseudoanaphylactic reactions
  display a similar clinical syndrome, but they are
  not immune-mediated. Treatment for the two
  conditions is similar

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Etiology

• Pharmacologic agents
• Antibiotics (especially parenteral penicillins
  and other ß-lactams),
• aspirin and nonsteroidal anti-inflammatory drugs
• intravenous (IV) contrast agents are the most
  frequent medications associated with
  life-threatening anaphylaxis.
• Latex
• Stinging insects
• ants, bees, hornets, wasps, and yellow
  jackets.
• Foods
• Peanuts, seafood, and wheat are the foods
  most frequently associated with life-threatening
  anaphylaxis.

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• Symptoms
• Common symptoms of a mild allergic reaction
  include
• Hives (especially over the neck and face)
• Itching
• Nasal congestion
• Rashes
• Watery, red eyes

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Anaphylactic reaction as it occurs in mast cells
and basophils.
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Symptoms

• Symptoms develop quickly, often within seconds or
  minutes. They may include the following
• Abdominal pain
• Abnormal (high-pitched) breathing sounds
• Anxiety
• Chest discomfort or tightness
• Cough
• Diarrhea
• Difficulty breathing
• Difficulty swallowing
• Dizziness or light-headedness 
• Hives, itchiness
• Nasal congestion
• Nausea or vomiting
• Palpitations
• Skin redness
• Slurred speech
• Swelling of the face, eyes, or tongue
• Unconsciousness

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Signs and tests

• Signs include
• Abnormal heart rhythm (arrhythmia)
• Fluid in the lungs (pulmonary edema)
• Hives
• Low blood pressure
• Mental confusion
• Rapid pulse
• Skin that is blue from lack of oxygen or pale
  from shock
• Swelling (angioedema) in the throat that may be
  severe enough to block the airway
• Swelling of the eyes or face
• Weakness
• Wheezing
• The health care provider will wait to test for
  the allergen that caused anaphylaxis (if the
  cause is not obvious) until after treatment.

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• Treatment
• Anaphylaxis is an emergency condition that needs
  professional medical attention right away. If
  necessary, begin rescue breathing and CPR.
• If the allergic reaction is from a bee sting,
  scrape the stinger off the skin.
• Take steps to prevent shock. Have the person lie
  flat, raise the person's feet.
• endotracheal intubation or tracheostomy or
  cricothyrotomy.
• The person may receive antihistamines, such as
  diphenhydramine, and corticosteroids, such as
  prednisone, to further reduce symptoms (after
  lifesaving measures and epinephrine are given).

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Allergic Angioedema/Urticaria

• Reactions are induced by histamine and mediated
  by IgE
• IgE mediated hypersensitivity reaction
• Reaction with allergen induces the release of
  histamine and other mediators
• Result vasodilatation and edema

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Allergic Angioedema/Urticaria

• Biochemistry
• Dependent on presence IgE molec sp to proteins in
  causative agent
• IgE molec bind to patients mast cells
• Trigger rxn upon re-exposure to antigen

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Allergic Angioedema/Urticaria
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Allergic Angioedema/Urticaria

• Inciting Agents
• Medications
• Foods
• Latex
• Environmental (includes insect bites)

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Allergic Angioedema/Urticaria

• Clinical Presentation
• Highly variable
• Depends on
• prev sensitization
• type of allergen
• /- urticaria
• (pruritic)

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Allergic Angioedema/Urticaria

• Clinical Presentation
• Often seen in patients with other allergic
  conditions
• Atopic dermatitis
• Allergic rhinitis
• Asthma

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Feature Angio-oedema Urticaria
Tissues involved Subcutaneous and submucosal surfaces. Epidermis and dermis.
Organs affected Skin and mucosa, particularly the eyelids, lips and oropharynx. Skin only
Duration Transitory (between 24-96 hours). Transitory (usually lt24 hours).
Symptoms Pruritus may or may not be present. Often accompanied by pain and tenderness. Pruritus is usually present. Pain and tenderness are uncommon.
Physical signs Erythematous or skin-coloured swellings occurring below the surface of the skin. Erythematous patches and wheals on the surface of the skin.
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• Urticaria

• Urticaria

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Physical urticaria

• Solar urticaria

Cold urticaria
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Physical urticaria

• Aquagenic urticaria

• Heat urticaria

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Physical urticaria

• Cholinergic

Dermatographic
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Angioedema
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Angioedema on tongue
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Algorithm for diagnosis of angio-oedema due to
C1-inhibitor deficiency.
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Skin Prick Test (SPT)
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Allergic Angioedema/Urticaria

• Management
• As always, airway first
• AAE does respond to
• Steroids
• H1 and H2 blockers
• subcutaneous epinephrine
• antihistamines.

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