Arm long bumps may be keratosis pilaris, folliculitis, urticaria, etc., need to clarify the specific causes of the choice of appropriate treatment, can be used externally or oral medication, etc., arm bumps continue to do not disappear, it is recommended to seek medical attention. 1. Keratosis pilaris: it occurs on the extensor side of the limbs, manifested as brown pimples consistent with the distribution of hair follicles, generally no treatment, or topical retinoic acid ointment, salicylic acid ointment, etc. to soften the keratin, to improve the symptoms, the use of medication, please follow the doctor’s instructions. 2. Folliculitis: usually manifested as red pimples, and may also be accompanied by itching, can be applied externally with erythromycin ointment, mupirocin ointment, please follow the doctor’s instructions. 3. Urticaria: caused by allergies, should be away from allergens, can choose to take oral antihistamines loratadine, cetirizine, etc. to improve the itching symptoms, the use of medication please follow the doctor’s instructions. The small bumps on the arm need to consult a doctor in a timely manner to clarify the cause of the disease.