Shingles may appear on the arms. Herpes zoster is caused by varicella-zoster virus infection. The rash of shingles usually occurs on one side of the body, most often on the lower back, and may occur on other parts of the body, such as the head, face, neck, chest, abdomen, and extremities. Herpes zoster is a contagious disease, after childhood infection, there may be no clinical symptoms, or chickenpox, after getting better, the virus will be latent in the body, in the decline of resistance or other triggers occur when re-infection, a series of symptoms, the onset of the disease is usually the first erythema, followed by the emergence of millet to soybean-sized pimples, in a cluster-shaped distribution without fusion, with the development of the disease will rapidly change into blisters. The virus is contagious and should be prevented until the last blister has crusted over. If you suspect that you have shingles, you should seek medical attention in a timely manner to confirm the diagnosis based on examination and clinical symptoms.