Hives look like raised red or pale-colored welts on the skin. They cause severe itching and can migrate from area to area over the course of time. They may even be accompanied by localised swelling, called angioedema. A doctor should always evaluate the appearance of the hives to distinguish them from other pregnancy-associated rashes such as autoimmune progesterone dermatitis of pregnancy and pruritic urticarial papules and plaques of pregnancy, or PUPPS. An allergist or immunologist may be called on to perform allergy testing, if needed, to help determine the cause.
Pregnancy-associated hives are usually easily managed with over-the-counter antihistamines. Your doctor may suggest diphenhydramine, sold as Benadryl; loratidine, known as Claritin; or cetirizine, sold as Zyrtec. Occasionally, more aggressive treatment may be necessary to control and eliminate the symptoms. It is always best to make sure your obstetrician is aware of your hives and of any medications that you may be taking to treat them.