General Medical Officer (GMO) Manual: Clinical Section

Urticaria and Angioedema

Department of the Navy
Bureau of Medicine and Surgery
Peer Review Status: Internally Peer Reviewed

(2) Acute urticaria (and/or angioedema) is very common, occurring at some point during the lifetime of about a quarter of the population. In about a third of the cases, the cause is a food or drug, and the patient makes the obvious connection, for instance, hives immediately after eating shrimp or beginning an antibiotic. In the rest, no cause is ever found, although the problem is self-limited and lasts less than 2 weeks. Atarax or benadryl is the standard symptomatic treatment with sedation often being a problem; the nonsedating antihistamines astemizole (Hismanal) 10 mg qd or terfenedine (seldane) 60 mg bid can also work well, as does a short course of PO prednisone 40-60 mg qd in more severe cases. Lab testing or specialty consultation is generally not necessary.

(3) Chronic urticaria (and/or angioedema) refers to a duration longer than 4-6 weeks. In contrast to the acute variety, it is only rarely caused by IgE mechanisms such as food or drug allergy. In fact, more than 90 percent of the cases turn out to be idiopathic, or of unknown cause. The prognosis for eventual spontaneous resolution is good, and most of the patients are healthy adults for whom the symptoms are nothing more than a nuisance. However, rare cases are associated with underlying malignancy, liver disease, autoimmune disease such as lupus, and inapparent infection, so a careful history, review of systems, and physical exam is recommended. If there is no weight loss, fever, malaise, or pint symptoms, idiopathic will probably be the diagnosis, and the patient should probably be told that a cause is unlikely to be found. As screening tests, a CBC, differential, ESR, perhaps an ANA, and total hemolytic complement are reasonable. Cholinergic (heat-induced) and cold urticaria are physical urticarias sometimes confused with the chronic form. Cholinergic hives occur consistently with exercise or hot showers (often like heat rash or prickly heat); while cold urticaria is precipitated by swimming in cold water or by cold weather, and is usually apparent in the history. Treatment of chronic urticaria is the same as for the acute forms. An excellent review article is in the Journal of Allergy and Clinical Immunology, vol 72, page 1, July 1983.

Prepared by: David B. Moyer, CAPT, MC, USN, Naval Hospital, Oakland, CA 94627, Specialty Leader for Allergy/Immunology, phone (510) 633-5927/5377, DSN 828-5927/5377