Allergy in body. Can u help me out?

You could be having hives or urticaria. Hives, also called urticaria, are circumscribed swellings on the skin that often are itchy. Hives happen when the cells in the skin called mast cells release histamine, a chemical that causes tiny blood vessels (capillaries) to leak fluid. When this leaking fluid accumulates in the skin, it forms the swellings that we recognize as hives. Hives can be triggered by physical factors such as heat, cold, exercise, sunlight, stress, sustained pressure on a skin area (such as from a belt or shoulder strap), a sudden increase in body temperature (from a fever or a hot bath or shower) or from an irritating chemical, cosmetic or soap applied to the skin. Hives also can be one symptom of a whole-body (systemic) allergic reaction to something that was: Inhaled — Pollens, animal dander, molds Injected — Insect stings or bites, especially bee stings, or injected medication Ingested — Foods (tree nuts; fish and shellfish; dairy products; legumes, especially peanuts), food additives, medications such as penicillin or aspirin Hives can affect skin on any area of the body, especially the trunk, thighs, upper arms and face. Most individual hives fade quickly, but new crops may appear every 24 to 72 hours if the person continues to be exposed to the environment or substance that triggered the hives.