Hello and welcome to healthcaremagic I would keep a possibility of Acute Urticaria. It presents as itching and skin welts/swellings, which can be distributed all over the body. Urticaria OR hives can occur due to various causes like(to name a few): --Infections(bacterial , viral, fungal) --Drugs(Pain killers/ antibiotics etc) --Certain foods and food additives/preservatives --Physical Urticaria: Cold temperature, Heat, Pressure(Prolonged Standing, Sitting), Dermaographism etc. --Cholinergic Urticaria: in response to strong emotions, exercise, spicy food etc --Autoimmune disorders like SLE, RA etc. --A few cases have no underlying cause and are known as idiopathic urticaria. I would advice you to get few basic lab tests like Hemogram, stool for ova/cyst, Urine routine, Chest X-Ray. An oral antihistamine like Fexofenadine (Allegra 180 mg tab) OR Loratadine (Alaspan 10mg tablet) once or twice daily for a week would be suitable. They are non-sedating and wont affect your alertness level. If I was your treating doctor I would have also given you a shot of injectable antihistamines like Avil(pheniramine) and Injectable effcorlin(hydrocortisone) for rapid relief. A topical soothing lotion like calamine would help you symptomatically. take care regards