Hives are recognized as red skin with an elevated, itchy, white area or welt. Benadryl (diphenhydramine is the generic) is usually found in a concentration of 12.5mg per 5cc and may be used to treat both hives from allergies and the itchy rash of scabies. It is available now as a clear, bubble gum-flavored liquid without dyes. The dose is 1 mg per kilogram of weight, given as often as every 6 to 8 hours. Thus, for a 6kg child: 6kg x 1mg per kg equals 6mg which equals 2.5ml (1/2 teaspoon) of Benadryl. Please remember that antihistamines commonly cause sleepiness. About 3 percent of children and adults do have an idiosyncratic reaction of hyperactivity. This reaction can occur even after the medication has been used and has caused no reaction at all. This medication is not recommended to control behavior on airplanes!