Children with small bumps on the arm like acne may be caused by perifollicular keratosis, folliculitis, milia, papular urticaria and so on, the patient should consult a doctor in time to clarify the cause of the disease. 1. Keratosis pilaris: also known as hair moss or keratosis pilaris, is a chronic follicular keratosis pilaris skin disease, and genetically related. The incidence of perifollicular keratosis is high, often starting in childhood, the lesions are obviously aggravated in puberty, and then relieved in adulthood, which can be manifested as small bumps on the arms of children like acne, and strengthen the moisturizing can improve the symptoms. 2. folliculitis: children’s arms have small bumps like pimples and red, swollen, pain, should be considered to be staphylococcus aureus and other infections caused by folliculitis, patients should do a good job of local skin cleaning. 3. Corns: If the child is in the summer there are small bumps on the arm like pimples, should be considered to be high humidity and high heat environment caused by the corns caused by the general stay in a cooler environment after a few days can subside on their own. 4. papular urticaria: children’s arms with small bumps like pimples may also be mosquito bites caused by papular urticaria, mostly accompanied by intense itching, itching may interfere with sleep, can be used under the guidance of a doctor, loratadine, cetirizine, etc. for treatment.