Rottenness in the folds behind the infant’s ears may be caused by high indoor temperature, eczema, trauma, etc. It can be relieved by keeping the indoor temperature suitable, avoiding contact with allergens and applying antibiotic ointment. 1. High indoor temperature: Rottenness in the folds behind the baby’s ears may be caused by excessive sweating due to high indoor temperature, resulting in erosion and swelling of the skin behind the ears. You can maintain a suitable temperature indoors, ventilate the room frequently, and scrub it clean in time when you sweat a lot. 2. Eczema: Babies’ skin is tender, and if skin allergy occurs, eczema may appear. It can be avoided by avoiding contact with allergens such as dust, animal dander, etc., and breastfeeding mothers are advised not to consume ingredients that are likely to cause skin allergies. 3. trauma: the child behind the ear ulcers, may be accidentally scratching caused by infection, you can apply antibiotic ointment such as erythromycin ointment, mupirocin ointment, etc. to prevent infection, to keep the local clean and dry, to avoid the baby to scratch with their hands. If a baby has a rotting behind the ear folds, it is recommended to consult a doctor in time, follow the doctor’s instructions to use medication, under the guidance of the doctor, to take the appropriate treatment program. All of the above medications should be used under medical supervision.