Urticaria is not contagious.

Urticaria, also known as wheals or commonly referred to as hives, is caused by temporary increased vascular permeability in the skin and mucous membranes due to allergic factors, resulting in localized edema. Wheals generally subside quite quickly, typically within 24 hours. The causes of wheals, which are essentially urticaria, may include the food we eat, airborne inhalants, and skin contact with substances such as pollen, dust mites, mold mites, as well as animal dander, fur, etc.

Additionally, some cases may be related to infections, and some people may have a lethal factor due to suspicious medications. Moreover, the occurrence of urticaria can also be related to other factors such as cold, heat, ultraviolet light, and mechanical stresses such as friction or pressure. Furthermore, other factors including psychological and endocrine factors can also lead to the occurrence of urticaria.