AAD: Urticaria
Information from the American Academy of Dermatology. Site also has a directory of dermatologists.

AAIR: Urticaria
Excellent information from Asthma & Allergy Information & Research (UK) on the different types of urticaria (hives).

ACAAI: Urticaria
Excellent information on all types of urticaria from the American College of Allergy, Asthma & Immunology.

Dermnet: Urticaria
Information with photographs from the New Zealand Dermatological Society.

Emedicine: Solar Urticaria
Medical information on solar urticaria.

Solar Urticaria
Information from the Photobiology Unit, Department of Dermatology, Ninewells Hospital & Medical School (UK).

Solar Urticaria (Korean)
Information in Korean (requires Korean character set).