There are many causes of spots on the body, such as lichen planus, solar dermatitis, post-inflammatory hyperpigmentation, seborrheic keratosis, and so on. 1. lichen planus: Malassezia infection can cause lichen planus, which may cause hypopigmented spots on the body, thus appearing the phenomenon of long spots on the body. 2. Solar dermatitis: long-term sunlight irradiation makes melanocyte overgrowth and secretion of melanin particles, which may also lead to sun spots on the body, resulting in the phenomenon of long spots on the body. 3. Post-inflammatory hyperpigmentation: for example, some chronic inflammatory skin diseases (such as eczema, atopic dermatitis, etc.) may cause skin hyperpigmentation after healing, resulting in spots on the body. 4. Seborrheic keratosis: may be caused by light aging epidermal benign tumors, manifested as light brown flat skin rashes or plaques, resulting in the phenomenon of long spots. Long spots on the body may also be caused by other diseases, such as neurofibroma, etc. It is recommended that patients go to the hospital in time for examination, after a clear diagnosis under the guidance of the doctor standardized treatment.