Hello, I understand your concern for the itching on the arms. After reading your query it appears to be related to scabies mite infestation. It is is quite common ot find such kind of clinical manifestation where typically there is more itching at night time. In my patients I suggest them to apply a cream or lotion containing permethrin 5 % over night application for once a week. An antihistamine tablet such as cetrizine helps in reducing the itching of various areas. Simultaneous treatment of the other family members and your pet is also quite important to take care of the problem completely. If despite above measure the things are not better then should meet a dematologist. All the best.