MedicineNet: Hives - Doctor written consumer health information on this condition, the different types of hives, causes, and treatment. Urticaria Pigmentosa - Causes, prognosis and treatment. DermNet - Urticaria - Information on different types of hives, including cholinergic urticaria and dermographism. NHS Choices: Urticaria (Hives) - Provides information on this raised, red, itchy rash. Includes a skin slideshow and details of symptoms, causes, diagnosis, treatment and complications. DrGreene.com - Hives - Read an article explaining a common rash and its many causes. eMedicine Health - Hives and Angioedema - Consumer health resource center providing information on the causes, symptoms, and treatment. Medscape - Urticaria - Pathophysiology, frequency, mortality/morbidity rate, causes, treatment, laboratory studies and medications. Patient: Urticaria - Factsheet on this condition, including its epidemiology, causes, presentation, differential diagnosis, investigations, management and prognosis.