Chronic Urticaria

Chronic urticaria

        The physician must differentiate urticaria from:

• Insect bites;
• The erythema multiform;
• Prurigo;
• First mastocytosis

        When urticaria is deeper, lesions are located in the deep dermis and hypodermis. This is an angioedema or urticaria subcutaneous acute. We distinguish edema hereditary angio-neurotic and especially angioedema or angioedema. Hereditary angioedema is very rare. It is characterized by episodes of edema of the glottis and intestinal edema. This condition is associated with a deficiency of serum inhibitor of C1 esterase fraction of complement. Angioedema is a deep hives sharing mechanism and causes of common urticaria.

        Injuries settle within a few hours and rarely persist more than 1 or 2 days. The angioedema reached areas with loose skin: the face (lips, eyelids), the genitals. The location at the pharyngo-laryngeal mucosa can cause fatal suffocation by swelling of the glottis. Impairment of gastrointestinal mucosa can cause digestive disorders.

Angioedema on the face should not be confused with:

• An acute eczema;
• erysipelas;
• An acute dermatomyositis

The contact urticaria

        It is a rash that appears immediately (15 to 30 minutes) after the contact of certain substances on the skin, so different from the allergic contact eczema that appears 48 hours after contact. The contact urticaria seat early at the site of application of the substance responsible. It can then grow and spread. It may be accompanied by angioedema (angioedema), an asthma attack or anaphylactic shock.

        Many substances are responsible for:

• Plant products:nettles, cedar, ivy, primrose, parsnips, sagebrush, marine plants (algae, lichens);
• Animal products:urticants marine animals (shellfish, jellyfish, fish), arthropods (processionary caterpillars, butterflies), spiders, animal hair (cow), saliva of the cat, dog or horse ... ;
• Food: bananas, peanut butter, egg whites, carrots, chicory, spices, flour, lettuce, turnips, walnuts, apples, potatoes, meat (lamb, turkey ...) etc .
• Textiles: wool, silk, products of dyes;
• Cosmetics: toothpaste, deodorants, hair lacquers, perfumes (cinnamic aldehyde, balsam of Peru), soaps, nail varnish, ammonium persulfate (hair bleach), preservatives (formalin, benzoic acid, sorbic acid);
• Industrial Agents:ammonia, exotic wood, formaldehyde;
• Drugs: bacitracin, balsam of Peru, cephalosporin, chlorpromazine, dimethylsulfoxide (DMSO), neomycin, penicillin, benzoyl peroxide, streptomycin;
• Human semen.

        A crisis of urticaria often occurs when operating in isolation for a few hours or days. This type of urticaria may cover 20% of the population. An allergic cause can be found: medicines, foods, insect stings and latex, for example, may be involved.