When an allergy occurs in a 4-month-old infant, the first thing to do is to closely observe the environment in which the child lives and is exposed to objects, and try to find the source of the allergy and avoid contact immediately. At the same time, if the child is breastfeeding, the mother should avoid spicy and irritating foods and eat more vegetables and fruits to supplement vitamins and ensure the child’s nutrition and diet to remove allergic factors. In addition, when bathing or rubbing the child, avoid using alkaline toiletries and try to use acidic toiletries such as boric acid soap or herbal rubs and lotions such as Pediatric Skin Care Rub. If the symptoms are not relieved, antihistamine and anti-allergy treatment can be administered, and the child can be treated with oral loratadine syrup.