Urticaria-contact =الشرى بالتماس |
|
|
|
Contact Urticaria
Urticaria may occur after direct contact with a variety of substances. It may be IgE mediated or nonimmunologic. The transient eruption appears within minutes, and when it is IgE mediated, it may be associated with systemic manifestations. Passive transfer has been documented in some instances. Proteins from latex products are a prominent cause of IgE-mediated contact urticaria. Latex proteins also may become airborne allergens, as demonstrated by allergenloaded airborne glove powder used in inhalation challenge tests. These patients may manifest cross-reactivity to fruits, such as banana, avocado, and kiwi. Associated manifestations include rhinitis, conjunctivitis, dyspnea, and shock. The risk group is dominated by biomedical workers and individuals with frequent contact with latex, such as children with spina bifida. Agents such as stinging nettles, arthropod hairs, and chemicals may induce release of histamine directly from mast cells
|