A light brown spot on the forehead of a baby may be a coffee spot, a mole, or a florid chaff rash. 1. Coffee spot: Coffee spot is a kind of birthmark, mostly related to heredity, part of the fetus can exist at birth, can also appear gradually in the first few months of life, the color is light brown, brown to dark brown, is a kind of pigmented lesions appearing on the surface of the skin. In addition, if it is a child with neurofibromatosis, it can also be accompanied by multiple lumps all over the body, coffee spots and other symptoms. 2. Nevus: Nevus is a kind of limited lesion on the skin, which may be related to developmental defects, heredity, gene mutation and other factors, and light brown spots may also appear on the forehead of infants if they have nevus. 3. florid chaff rash: florid chaff rash is a superficial infection caused by Malassezia violating the cuticle of the skin, lesions can be brown, light brown dotted rash, babies suffering from this disease may also appear light brown spots on the forehead. In addition to the above factors, other causes can also lead to light brown spots on the forehead of babies. Parents should take their babies to the hospital as soon as possible, ask the doctor to help identify the cause and give treatment if necessary.