Urticaria, commonly known as hives, appears as red, itchy welts on the skin. There are several types, including acute urticaria, which lasts less than six weeks and is often triggered by infections, foods, or medications. Chronic urticaria persists beyond six weeks and may be linked to autoimmune conditions. Physical urticaria occurs due to triggers like heat, cold, or pressure, while cholinergic urticaria arises after exercise or stress. Drug-induced urticaria can result from medications such as antibiotics; for example, some people may experience reactions while taking cephalexin capsules. Identifying the cause helps guide treatment, often with antihistamines and trigger avoidance.