A child with a patch of small bumps on the chin may be related to eczema, atopic dermatitis, folliculitis and other causes, and need to be further differential diagnosis by the doctor. 1. Eczema: on the basis of skin erythema, many pimples of the size of a pinhead to a grain of corn will appear. 2. Allergic dermatitis: Ultraviolet light and other allergens can enter the human body through the skin and other channels, leading to an abnormal immune response, which can lead to the phenomenon of a small lump on the chin. 3. Folliculitis: If the chin is infected with bacteria and other pathogens, it can cause an inflammatory reaction, leading to folliculitis, resulting in a small pimple on the chin. It is recommended that parents take their children to the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.