There are several possibilities to consider when pinpoint-sized red dots appear on the arms. Firstly, it is considered to be perifollicular keratosis, which is characterized by pinhead-sized follicular papules symmetrically distributed on the lateral side of both forearms and the lateral side of both thighs, with a rough surface, and similar phenomenon can be seen on both cheeks in some patients, and can be treated with topical urea cream or retinoic acid cream, which aims to improve the symptoms and cannot be cured. Second, consider folliculitis, early folliculitis can be manifested as pinpoint-sized red papules, not accompanied by pain, later local pus can appear, local antibiotic creams can be used topically, such as fusidic acid cream. It is also possible to consider the possibility of dermatitis, manifested as a local pinpoint-sized red spot or erythema, part of the rash can be fused into pieces, can be treated with topical glucocorticoid creams.