A lot of tiny bumps on the arms of small children, may be perifollicular keratosis, friction moss, Malassezia folliculitis, etc., you can choose different topical drug treatment. 1. Keratosis pilaris: the cause is unknown, may be related to genetic factors, vitamin A deficiency, metabolic disorders, manifested in the outer side of the upper arm pinpoint size dense keratosis pilaris, can be used externally with salicylic acid ointment, retinoic acid ointment to soften the dissolution of keratin, improve the symptoms. 2. Friction moss: mostly occurs in the hands, wrists and small arms, with the children long-term contact with sand, water, plastic toys and other allergic reactions caused by, can be used externally fluoride easy cream, compound dexamethasone ointment and other glucocorticosteroid medications, with anti-inflammatory, antipruritic effect. 3. Malassezia folliculitis: a variety of reasons for the decline in immunity, the skin barrier function is weakened, resulting in Malassezia folliculitis, can also cause a lot of small bumps on the arm of the child, can be used topical clotrimazole ointment, terbinafine ointment and other drugs treatment. Children with a lot of tiny bumps on the arm, you need to go to the hospital for examination, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.