Causes listed below are organized by groupings.
Physical
Aquagenic urticaria: Caused by contact with water.
Cholinergic urticaria (or "prickly heat rash"): Caused by physical exercise, overheating, and mental stress. Can be brought on by a warm bath/sauna, eating hot spices, and alcohol consumption.
Cold urticaria: Caused by contact with cold breezes, temperatures, and surfaces. This type may be associated with viral/parasitic infection, syphilis, multiple insect bites, penicillin injections, dietary changes, and stress.
Dermatographic urticaria: Caused by pressure, stroking, scratching, and rubbing and may be brought on by contact with another person, furniture, bracelets, watch bands, towels, and bedding. This type may be associated with parasite infection, insect bites, hormonal changes, thyroid disorders, pregnancy, menopause, diabetes, immuological alterations, other urticarias, drug therapy, chronic candidiasis, angioedema, and increased blood levels of the white blood cell eosinophils.
Exercise-induced anaphylaxis: Caused by exercising after a heavy meal.
Familial cold urticaria: Caused by cold wind and change from cold to warm air.
Heat urticaria: Caused by heat.
Pressure urticaria: Caused by pressure.
Solar urticaria: Caused by light of varying wavelengths.
Vibratory angioedema: Caused by vibration.
