What causes urticaria?
While acute urticaria is commonly set off by infections, it may be related to a food, medication or even contact with a plant, insect sting or animal.
In chronic urticaria, 80% of the time no cause can be identified. Some urticaria that is chronic is physical in nature but often it may be related to an underlying autoimmune condition.
Chronic urticaria is rarely allergy in aetiology. Thyroid autoimmunity, connective tissue disease, urticarial vasculitis and even hormones, medication or infections may be responsible for chronic urticaria.