THE urticaria is characterized by the rapid appearance of skin lesions known as urticals, which are red, highly pruriginous lesions. Usually the lesions have a short duration (less than 24 hours).
It can be classified according to duration in acute, when it lasts less than six weeks, or chronic when it lasts longer than six weeks.
Urticaria may have several causes, as:
- Induced by antigens: allergy to drugs, insects and food;
- Mediated by antibodies: cold urticaria, symptomatic dermographism and solar urticaria
- dermographism: onset of lesions 1 to 5 minutes after application of mechanical forces;
- late pressure urticaria: lesions appear after 3 to 8 hours of mechanical force application;
- cold urticaria;
- heat-related urticaria;
- urticaria vibratory;
- Associated with infections:
- viral hepatitis A or B, cytomegalovirus, coxsackie virus;
- bacterial: H. pylori, streptococci;
- fungi: Trichophyton sp, Candida sp.
- parasites: giardiasis, ascariasis, strongyloidiasis, amebiasis;
- Associated with internal diseases such as tumors and sarcoidosis.
- Special types: cholinergic urticaria, adrenergic urticaria, contact urticaria (allergic or pseudoallergic), aquagenic urticaria.
O diagnosis of urticaria is clinical and determining the cause is often challenging and depends heavily on the patient's perception of habits, medications or foods that can be triggered. Autoimmune infectious causes should always be investigated, as well as association with other diseases, especially haematological ones.
Treatment is often a challenge and is based on the use of antihistamines and the removal of triggering factors, as well as other medications in those more refractory cases.
The diagnosis and treatment of chronic conditions should be made by the physician dermatologist. In the presence of urtic-like lesions, see a dermatologist.
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