Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop into fluid-filled blisters (bullae). This condition is usually triggered by allergic reactions to insect bites, sensitivity to drugs, or other environmental causes. In some cases, swelling of the soft tissues of the face, neck, and hands (angioedema) may also occur.
Because it is difficult for children and adults to resist scratching these itchy crusted bumps, the possibility of infection is great and caution must be taken. Papular urticaria may accompany, or even be the first symptom of various viral infections including hepatitis, infectious mononucleosis, or German measles (rubella). Some acute reactions are unexplained, even when recurrent.
The first symptom of papular urticaria is usually itching (pruritus). This is followed shortly by the appearance of elevated ridges (wheals) that may remain small or become large. The larger wheals tend to be clear in the center, and may be noticed first as large rings of redness of the skin (erythema) and swelling (edema). Ordinarily, crops of hives come and go. A lesion may remain for several hours, then disappear only to reappear elsewhere.
Angioedema is a more diffuse swelling of loose tissue under the skin usually affecting the back of hands or feet, lips, genitalia and mucous membranes. Swelling (edema) of the upper airway may produce respiratory distress, and the high-pitched tone of difficult breathing may be mistaken for asthma.
Acute papular urticaria and angioedema are essentially exaggerated allergic reactions limited to the skin and tissues just under the skin (subcutaneous tissues). The reaction may be caused by a drug allergy, by insect stings or bites, by desensitization injections (allergy shots) or ingestion of certain foods (particularly eggs, shellfish, nuts or fruits) by people who are allergic to these substances. In some cases (such as reactions to strawberries), the reaction may occur only after overindulgence, and possibly result from direct toxic histamine release into the blood. If acute angioedema is recurrent, progressive, and never associated with urticaria, a hereditary enzyme deficiency should be suspected.
Children from 2 to 7 years are most commonly, but not exclusively, affected by papular urticaria. Children are especially susceptible in the summertime when the insect population increases. It is more rare in adults, perhaps in part because adults build up a tolerance.
Acute papular urticaria is a self-limited condition that generally subsides in 1 to 7 days. Therefore, treatment is chiefly symptomatic. If the cause is not obvious, all nonessential medication should be stopped until the reaction has subsided. Symptoms such as itching and swelling can usually be relieved with a topical soothing agent such as calamine lotion or oral antihistamine. Corticosteroids (e.g. prednisone) may be necessary for the more severe reactions, particularly when associated with angioedema. Topical corticosteroids are of no value. More serious attacks may bring on airway obstruction that may require an opening in the trachea (tracheotomy).
Although the specific cause of chronic papular urticaria can seldom be identified and removed, spontaneous remissions usually occur within 2 years in about half of the cases. Control of stressful life situations often helps. Certain drugs (e.g. aspirin) may aggravate symptoms, as can alcoholic beverages, coffee and tobacco. If so, they should be avoided.
Oral antihistamines are beneficial in most cases. All reasonable measures should be used before resorting to corticosteroids, which are frequently effective but have significant side effects after chronic use. A few patients with urticaria that doesn't respond to treatment (intractable) may have a hyperthyroid condition.
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Stibich AS. Papular Urticaria. emedicine. Last Updated: June 4, 2003. 7pp.