Black forehead skin may be caused by physiological factors such as long-term sun exposure, and may also be related to post-inflammatory hyperpigmentation and melanosis.
1. Physiological factors: If you usually do not do a good job of facial sunscreen, long time sun exposure will lead to activation of melanocyte function, resulting in the phenomenon of forehead skin darkening.
2. Post-inflammatory hyperpigmentation: post-inflammatory hyperpigmentation is an acquired pigmentation abnormality, if the forehead part once suffered from acne, impetigo, dermatitis and other diseases, may lead to inflammatory reaction of the skin, and after the inflammation subsides, it will be hyperpigmented, which will be manifested as dark forehead skin.
3. Melanosis: Melanosis is a kind of pigmentation disease, and contact with coal tar, the use of poor quality cosmetics or special drugs, the disease appears in the forehead, the forehead skin black phenomenon.
There are many reasons for the darkening of the forehead skin, and it is recommended to consult a doctor for examination after physiological factors have been ruled out.