Blister-like bumps on the arms may be caused by shingles, papular urticaria, eczema and other causes. 1. Herpes zoster: a skin disease caused by infection with varicella zoster virus. Before the onset of rash, there may be mild fatigue, low fever, loss of appetite and other systemic symptoms. The affected skin may have burning heat or burning pain, and there is obvious pain sensitivity to touch. Rash period, the first flushed spot, and then soon appeared millet to soybean size papules, followed by rapid change into blisters. 2. Pimple urticaria: occurs with insect bites, common such as fleas, lice, mites and so on. The main manifestation is the appearance of bright red, windswept papules on the skin, and there may be blisters, pustules or crusts on the top of the lesions. 3. Eczema: Its occurrence may be related to abnormal immune function and skin barrier dysfunction. It often manifests itself as pinhead to corn-grain sized papules and papules on the basis of erythema, and small blisters may appear in severe cases. In addition, it is recommended to go to the hospital in time for the blister-like bumps on the arm, and follow the doctor’s instructions for treatment to avoid delaying the condition.