n.
or urticaria
Allergic skin reaction in which slightly raised, flat-topped, very itchy swellings appear suddenly.
The acute form, probably most often caused by food allergies , subsides in 624 hours, but the chronic form, believed to be due to emotional and mental stress, lasts much longer. Acute hives may also be triggered by drugs, especially penicillin , inhaled allergens or toxins , or diseases. Treatment involves identifying and avoiding the allergen; epinephrine and antihistamines may help the acute skin symptoms.