My Dear Welcome to Healthcaremagic! From your description I think your son has got urticaria which is a condition in which various sized wheals appear anywhere over the body, usually stay for less than 24 hours, to reappear again and do not have a fixed location or pattern. These are generally due to some allergy the cause for which may or may not be apparent. Most patients with this condition would get significant improvement by anti allergic orally and calamine lotion locally It has to be treated by steroids if the patient develops breathing difficulty or severe difficulty in swallowing. Patients are advised to refrain from spicy foods, artificial food additives, egg preparations . nuts and other chemicals like room fresheners and perfumes. It helps to get basic investigations like CBC, Urine routine, and stool examination done to rule out common infections. In general the condition responds very well to treatment suggested above. Hope that your son too gets well soon Best wishes