Brown dots in the middle of the chest may be pigmented spots or caused by factors such as lichen planus. 1. Pigmented spots: It is considered that the uneven distribution of melanin particles in the skin leads to the appearance of darker-than-normal spots on the local skin. The causes of pigmentation spots are complicated, which may be triggered by excessive sun exposure, improper use of cosmetics, endocrine disorders or chronic liver and gastrointestinal diseases. 2. lichen planus: it may also be caused by local skin infected by malassezia, which can occur in the face and neck, chest, shoulders and back and other parts of the sebaceous glands are relatively rich. It will show brown, light brown or light red spots. This phenomenon also needs to go to the hospital in time, because the middle of the chest with brown dots is not entirely caused by pigmentation spots, lichen planus and other factors.