Many white dots on the arms need to be judged by observing the size of the white dots, their area, the presence of bumps and whether they are accompanied by other symptoms, such as whether they are itchy and painful, to determine the specific disease and the subsequent treatment. If a large area of white dots or self-conscious discomfort, it is recommended to consult a dermatologist and conduct the appropriate skin examination to confirm the diagnosis and avoid generalization: I. Types of diseases: 1. Boils: Mostly caused by inattention to local skin hygiene, the lesions are follicular inflammatory papules, which later expand to the surrounding area and form hard nodules with redness, swelling, heat and pain, and after a few days yellowish-white punctiform pustules will appear at the top, and white dots are visible on the arms; 2. Vitiligo: May The typical lesions are milky white or porcelain white pigment loss spots with clear borders, without atrophy, sclerosis and hypertrophy, often without conscious symptoms; 3, pityriasis: mostly caused by Malassezia infection, invasion of skin stratum corneum, with a certain genetic susceptibility. Initially for point-like rash, can be white, gradually increase to nail cover size, round or round-like, adjacent lesions can fuse with each other into irregular large patch, surface covered with furfuraceous scales. Usually no conscious symptoms, occasionally mild itching; 4, white furuncle: the cause of this disease is still unclear, clinical with varying sizes of round or oval light white spots, covered with furfuraceous scales as a feature. Second, treatment measures: 1, boils: can use 3% tincture of iodine, mupirocin ointment, 20% ichthyolite ointment and other topical application; 2, vitiligo: can use 0.1% tacrolimus ointment application, but also phototherapy, depigmentation therapy, are effective; 3, pityriasis furfur: can use antifungal topical preparations, such as ketoconazole cream, miconazole cream, clotrimazole cream, etc. for treatment; 4, pityriasis alba: topical application of emollient cream, such as Silicone oil cream, 5% urea ointment, 5% sulfur cream, 1% gentamycin ointment, 2% salicylic acid ointment, etc. are effective, also can take oral vitamin B complex or multivitamin pills.