Erythema caused by allergies does not usually leave scars. Daily exposure to allergens can lead to allergic reactions in the body, such as erythema, itchy skin, nausea, vomiting and diarrhea. Antihistamines are usually given for treatment, such as loratadine, cetirizine, etc., and emergency treatment is given to the patient if necessary. However, if the patient accepts the treatment actively, the symptoms of allergy will be relieved, and the red spots caused by allergy will fade away slowly, and there is no big difference between the red spots and the normal skin after the red spots have completely faded away, and there will not be any scarring in general. However, it is not recommended to scratch the local skin during the period of allergy, so as not to cause local skin damage, thus leaving scars. It is recommended that patients go to the hospital in time and follow the doctor’s instructions for standardized treatment.