Itchy skin, pimples when scratched.

The skin itch scratches on the pimple, there may be skin produced urticaria or allergic dermatitis. This is mainly due to the patient himself showed allergic reactions, especially due to eating specific allergic foods, or due to inhalation of certain allergic particles, resulting in allergic skin changes, so this time itching. However, after scratching this mechanical stimulation may induce certain skin lesions, such as showing wheals or inflammatory erythema.