Black patches on the waist are considered to be related to seborrheic keratosis, pigmented nevi, and post-inflammatory hyperpigmentation.
1. Seborrheic keratosis: Seborrheic keratosis is a kind of benign intraepidermal tumor, commonly seen in the elderly. The lesions are mostly found in the scalp, trunk, upper limbs, and can also occur in any part of the skin, resulting in localized dark brown patches or plaques, greasy thick scabs, and hyperpigmentation.
2. Pigmented nevus: pigmented nevus is a benign neoplasm composed of nevus cells and belongs to benign skin tumor. It is mainly manifested by the appearance of skin surface growths of uniform size, color and shape.
3. Post-inflammatory hyperpigmentation: With previous skin problems such as eczema, dermatitis, herpes zoster, etc., local inflammatory reactions may occur. After the treatment of the disease, the pigmentation is left behind, resulting in localized black patches. With the passage of time, most of them can reduce or disappear on their own.
Black patches on the waist, it is recommended to pay strict attention to sun protection, if necessary, to the hospital dermatology department to identify the cause, follow the doctor’s instructions standardized treatment.