Flashcards in Hypersensitivity Deck (10):
A 22 year old woman presents with an intermittently itchy and desquamating skin rash on her abdomen which is unresponsive to antihistamines.
Contact hypersensitivity: typical rash, in area where belt rubs.
A 35 year old woman presents with a two day history of a red itchy skin rash which started soon after her first scuba-diving lesson. She is otherwise well.
Acute urticaria: suggestive rash, after ?latex.
A&E, tongue swelling and acute respiratory tract obstruction. Blood pressure stable, Normal breath sounds. Medication includes cyclosporine, azathioprine, captopril and nifedipine.
Angioedema: no generalised allergic reaction. Most is drug-induced, mostly ACEi like captopril.
500 micrograms adrenaline (0.5ml).
Under 12yo: 300 mcg
Under 6yo: 150 mcg
Angioedema Tx (without anaphylaxis)
IV or IM antihistamines
Non-autoimmune - Re-exposure, IgG, mast cells.
Type I hypersensitivity - allergy.
Ab (IgG/IgM) to self
Type II hypersensitivity
IgG/IgM immune complexes
Type III hypersensitivity
Delayed response, T cell-mediated reaction
Type IV hypersensitivity