Hi and thanks for the query, from what you describe, this is purely an allergic reaction. A few things must be considered. Is ther any family history of atopy (allergy), asthma ? It is very important to be known, whether the child is experiencing this for the very first time is also important. A physical examination shall search for signs of acute inflammation, nature of lesions, redness, itches, eruptions and the degree and rapidity of spread. appropriate therapy first involves prescription of anti inflammatory drugs, usually steroids, which could be injectable or oral depending on the case, and an active search of an allergen. This is very important to determine the particular substance the led to symptoms. Eliminating or avoiding this allergen in future shall therefore avoid future episodes. Cutaneus anti histaminic drugs can be prescribed to diminish itching. When very recurrent of failure to respond to therapy, immmunosuppressive therapy under the supervision of an allergist might then be required. Consulting an allergist in very serious and drug resistant cases might be very important.