There can be multiple reasons for such a problem. It can be due to infection or due to diseases like pemphigus . The diagnosis can be correctly made only after seeing them and examining them
Next Steps
please consult a dermatologist in person at the earliest and get it treated
Health Tips
Atarax is just an antihistamine and it works only for allergy and itching. In this case it is not enough to correct the present problem. Depending on the cause your grandmother may sometimes even need to be treated with steroids