The baby’s arm has a patch of small rice grain bumps, which may be caused by eczema, urticaria, perioral keratosis and other factors. It is recommended to pay attention to skin moisturizing, topical antihistamine, glucocorticoids and other drugs. 1. Eczema: the cause of eczema is not clear, such as external factors of stimulation, heredity, autoimmune factors, resulting in skin pimples, papules with itching. Topical glycerin lotion and hydrocortisone cream can be used to relieve skin inflammation and improve itching symptoms. 2. Urticaria: Pediatric urticaria is a common clinical allergic skin disease, which may lead to the appearance of different sizes of erythema, doughnut lesions with itching. It is recommended to remove the triggers as much as possible, and give antihistamines such as cetirizine hydrochloride and loratadine if necessary, which can relieve the symptoms. 3. Keratosis pilaris: Keratosis pilaris in children is generally related to genetic factors, which can also lead to the appearance of rice-like bumps on the skin. Patients do not have any uncomfortable symptoms, usually do not need special treatment. If the symptoms are obvious, vitamin E, retinoic acid cream and other medications can be given. The appearance of rice-like bumps on the arms, accompanied by anorexia, vomiting, fever, but also to understand whether it is related to chicken pox, viral rashes and other diseases, it is recommended to consult the pediatrics or dermatology department of the hospital in a timely manner.