Etiologic Classification of Urticaria

Foods
Fish, shellfish, nuts, eggs, chocolate, strawberries, tomatoes, pork, cow's milk, cheese, wheat, yeast
Food additives
Salicylates, dyes such as tartrazine, benzoates, penicillin
Aspartame (NutraSweet) probably does not cause hives *
Sulfites
Drugs
Penicillin, aspirin, sulfonamides, and drugs that cause a non-immunologic release of histamine (e.g., morphine, codeine, polymyxin, dextran, curare, quinine)
Infections
Chronic bacterial infections (e.g., sinus, dental, chest, gallbladder, urinary tract), Campylobacter enteritis, fungal infections (dermatophytosis, candidiasis), viral infections (hepatitis B prodromal reaction, infectious mononucleosis, coxsackie), protozoal and helminth infections (intestinal worms, malaria)
Inhalants
Pollens, mold spores, animal dander, house dust, aerosols, volatile chemicals
Internal disease
Serum sickness, systemic lupus erythematosus, hyperthyroidism, autoimmune thyroid disease, carcinomas, lymphomas, juvenile rheumatoid arthritis (Still's disease), leukocytoclastic vasculitis, polycythemia vera (acne urticaria–urticarial papule surmounted by a vesicle), rheumatic fever, some blood transfusion reactions
Physical stimuli (physical urticarias)
Dermographism, pressure urticaria, cholinergic urticaria, exercise-induced anaphylactic syndrome, solar urticaria, cold urticaria, heat, vibratory, water (aquagenic)
Nonimmunologic contact urticaria
Plants (nettles), animals (caterpillars, jellyfish), medications (cinnamic aldehyde, compound 48/80, dimethyl sulfoxide)
Immunologic or uncertain mechanism contact urticaria
Ammonium persulfate used in hair bleaches, chemicals, foods, textiles, wood, saliva, cosmetics, perfumes, bacitracin
Skin diseases
Urticaria pigmentosa (mastocytosis), dermatitis herpetiformis, pemphigoid, amyloidosis
Hormones
Pregnancy, premenstrual flare-ups (progesterone)
Genetic, autosomal dominant (all rare)
Hereditary angioedema, cholinergic urticaria with progressive nerve deafness, amyloidosis of the kidney, familial cold urticaria, vibratory urticaria

* Geha, R, Buckley CE, et al: J Allergy Clin Immunol 1993; 92:513.