A lot of small red pimples rose on the chest what reason

A lot of small red pimples appeared on the chest, considering the following possibilities: 1. Folliculitis, mainly caused by embolism caused by excessive skin keratosis at hair follicles, sebum excretion disorder, or poor cleanliness, need to keep clean, topical clindamycin gel treatment;2. Allergic reaction, oral cetirizine, cyproheptadine or prednisone treatment, calamine lotion for external use, pay attention to keep away from allergens. 3. Acne, because there are a large number of sebaceous glands and hair follicles distributed on the chest, once the abnormal secretion of sebaceous glands is shown, it may show local acne reaction. After this situation, it is necessary to actively use topical drugs and oral drugs for treatment. Adapalene gel or clindamycin gel can be selected for local external application treatment.