[Round Table: Immunological urticaria mediated by IgE]

Abstract

Urticaria is characterized by the appearance of hives and pruritus. Those hives are formed by oedema and vasodilatation and they disappear when they are pressed on. The acute presentation is extremely common and affects between 10 and 20% of the population at a determined moment. In its simplest form, urticaria is envisioned to represent the same sort of wheal-and-flare reaction observed when histamine is injected into the skin. It produces erythema because of capillary vasodilatation, oedema because of increased permeability in capillary and pruritus secondary at local specific receptors stimulation. Angioedema is caused by the same pathologic alterations that occur in the deep dermis and subcutaneous tissue. Thus, an area involved with angioedema has swelling as the prominent manifestation and appearance of the skin itself may be normal. Due to reduced nerve supply in dermis, angioedema is associated with oppression and not pruritus. Immunoallergological study of urticaria and/or angioedema was requested in 133 cases from 648 from the first patient's visits to the surgery. It supposes a 20.52%. The family suspicion of etiology was food in 62 cases, chemical products in 39 cases, other factors (physical, stings, balloons and other manufactured products.) in 7 cases and 25 cases without a direct relation. Out of 100 children diagnosed of allergic urticaria-angioedema 67 was by food; the foods implicated in frequency order were: eggs and nuts, fruit, milk, vegetables, fish and shellfish. In second place, chemical products were responsible of urticaria in 12 children; five of them were positive in diagnosed proof (prick, oral challenge) for penicillin and amoxicillin, both from beta-lactamic group; two of them had and adverse reaction to anesthetic agents; other two cases were after administration of vaccination and due to tetanus toxin; and three cases were due to aspirin, confirmed by oral provocation test. In 10 children the etiological agent was latex. Other etiologies were: three cutaneous reactions after stings (two by wasps and one by mosquito) three reactions due to spices (paprika, cumin, anise, mustard) and two reactions caused by manufactures products containing additives as yellow-orange.