Hi. Thanks for posting your concern at HCM I would keep a possibility of Acute Urticaria secondary to preservatives/additives in chocolates. Urticaria OR hives can occur due to various causes like(to name a few): -Infections(bacterial , viral, fungal) -Drugs -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 Xray. An oral antihistamine like Fexofenadine OR Loratadine once or twice daily for a week would be suitable. They are non-sedating and wont affect your alertness level. A topical soothing lotion like calamine would help you symptomatically. take care regards