There are many reasons for acne on the skin: First, skin allergy, which leads to erythema, papules and wheal on the skin due to human contact with allergens. If it is skin papules caused by allergies, it is necessary to know your allergens, avoid contact with allergens, and apply anti-allergic drugs for treatment. Second, seasonal changes lead to excessive heat and dryness of environmental stimuli, which can cause rashes. For the treatment of eczema, antihistamines can be used to relieve itching, and emulsion can also be used to relieve it. Third, skin dermatitis and other problems may also induce red acne on the skin, or it may be caused by exuberant oil secretion, mosquito bites and mental factors. It is necessary to actively control infection and apply anti-inflammatory and antipruritic drugs to relieve symptoms.