urticaria bullosa

Urticaria bullosa is a rare type of allergic reaction that causes blisters, or bullae and vesicles, to appear on the skin. It is a form of urticaria, commonly known as hives, which are itchy, raised welts on the skin. These reactions are typically caused by the release of histamine from mast cells in the skin. Common triggers for urticaria include allergies to foods like shellfish, strawberries, and nuts, as well as drugs such as penicillin. Physical factors like cold, exercise, and sunlight can also cause hives. While most cases respond to antihistamine treatment, identifying and avoiding the specific allergen is key.12