Hi,
Your 12 year old son has already been seen by a
Dermatologist at a reputed Johns Hopkins for severe scratching, loss of eye brows, rash all over body, hives and so on without any results.
The most probable reasons can be as follows:
Allergy can be one of the commonest cause added by
multivitamin deficiency, any genetic disorder,
hormonal problems and so on.
I would advise you the following in such a case:
Consult a Pediatrician to rule out any instigating cause for the symptoms.
Have proper in depth investigations to rule out possible things.
Liver function.
Thyroid function.
Vitamin B 12, D and A estimations and if any deficiency then corrective doses under the guidance of the Pediatrician.
Then take a
second opinion of another Dermatologist nearby to have any additional treatment to have better results.
Also have a keen watch on the instigating and enhancing factors, foods, beverages and avoid all these once suspected or found.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. T. Chandrakant, General Surgeon