Hello,
The doctors are right in saying that it can be either an allergy or a viral infection.In my opinion,it can be either dermatitis like
eczema,
hives or rash of measles.
Eczema is a form of chronic dermatitis (rash).Allergic reaction is one of the important causes of eczema. Allergic reaction can occur to strong soaps, Solvents, chemicals, certain foods, food additives, plants, metals, cosmetics, even urine and faeces of some animals (dust mites).