Red spots on the arms that do not hurt or itch are generally considered to be caused by eczema or allergies, and in a few cases pityriasis rosea can also cause this condition. It is recommended to go to the hospital for examination to determine the specific cause of the redness and then treat the symptoms. If it is caused by allergy, look for allergens while using anti-allergy treatment with medication to avoid the recurrence of similar conditions. If eczema is the cause of the erythema on the arms, local application of Eloson ointment can be applied under the guidance of a doctor to relieve the symptoms. At the same time, pay attention to personal hygiene, change clothes and shower regularly, avoid eating spicy and irritating food to reduce the occurrence of eczema. Erythema above the arm caused by pityriasis rosea, in addition to local application of sulfur ointment, at the same time under the guidance of the doctor to take drugs for treatment, such as ten flavors of frankincense, golden cicada antipruritic capsule, etc.