Urticaria : definition/ diagnostic criteria Urticaria is described by the quick manifestation of wheals and this may be accompanied by angioedema. A wheal has three typical features which comprises: (i) a centrally located swelling of varying size, almost always encircled by reflex erythema; (ii) accompanied with itching or burning and; (iii) its transient nature, where the skin returns to normal appearance within 1 hour to 24 hours. (1) The transient nature of urticaria is an important characteristic of urticarial lesions. Each individual wheal classically persists for less than a 2day. In individuals suffering from physical urticaria, each individual wheal may last less than an hour. But with delayed pressure urticaria this rule is an exception where each individual wheal may last at least 8-48 hours and this is characteristic especially on the palms and in the soles. The typical urticarial lesion on physical examination, is a pale-to-red and a …show more content…
The reactive individual papules surround a wheal, which always often have a central punctum. The histopathological changes seen in papular urticaria comprises of mild subepidermal edema, extravasation of erythrocytes, interstitial eosinophils, and exocytosis of lymphocytes. Papular urticaria is characteristically a clinically challenging condition, especially during spring and summer months. (9) Papular urticaria is the outcome of hypersensitivity (id reaction) to bites certain insect bites such as mosquitoes gnats, fleas, mites, and bedbugs. These pruritic papules and papulovesicles seen most commonly in children suffering from papular urticaria is symmetrically distributed. Erosions and ulcerations result on account to itchng. Pyoderma is common. These lesions occur in crops.