Arm full of pimples on both sides of the arm may be corn, folliculitis, papular urticaria and other diseases caused by the patient should consult a doctor in a timely manner to clarify the cause of the corresponding treatment. 1. Corns: If the arm sides full of pimples before the patient in the high humidity and high temperature environment, should be considered to be caused by corn, generally in the high humidity and high temperature environment can be removed from the pimples can subside on their own, if necessary, you can use the prickly heat powder for treatment. 2. Folliculitis: arm full of pimples on both sides may be caused by folliculitis, the patient will also have arm redness, swelling, pain, and red pimples centered on hair follicles, for the infected pathogen, oral or topical antibiotics or antifungal drugs can be used for treatment. 3. papular urticaria: if the patient is in the grass, woods, after the arms full of pimples and with itching, should be considered mosquito bites caused by papular urticaria, can be used externally glucocorticosteroid drugs, oral loratadine, etc. for treatment. All of the above drugs should be used under the guidance of a doctor.