Allergy & Anaphylaxis
Gell & Coombs Hypersensitivity
- Type I — immediate, IgE-mediated (anaphylaxis, urticaria).
- Type II — antibody-mediated cytotoxic (IgG/IgM) (e.g., pemphigus).
- Type III — immune complex (e.g., SLE, serum sickness).
- Type IV — delayed, T-cell mediated (contact dermatitis).
Latex Allergy
Can be Type I (immediate) or Type IV (contact); use non-latex gloves for sensitised patients.
Anaphylaxis
First drug = intramuscular epinephrine (adult 0.3-0.5 mg, anterolateral thigh) + airway, oxygen, positioning; antihistamines/steroids are adjuncts.
Exam Tips ⭐
Type I = IgE (anaphylaxis); Type IV = T-cell (contact); anaphylaxis → epinephrine IM first.