The darkening of the skin on the waist may be caused by excessive sun exposure, post-inflammatory hyperpigmentation, friction stimulation and so on.
1. Excessive sun exposure: may be due to the waist long-term exposure to ultraviolet radiation, resulting in localized hyperpigmentation.
2. Post-inflammatory hyperpigmentation: If the skin of the waist is traumatized or has suffered from local eczema and other diseases, it is easy to lead to post-inflammatory hyperpigmentation, which may leave obvious scars or dark-colored patches.
3. Friction stimulation: it may be due to the waist is often subject to friction stimulation, for example, often by the belt, pants waist friction lead to skin blackening.
The darkening of the skin of the waist may also be caused by other reasons, if there is no obvious discomfort symptoms, do not need special treatment, if accompanied by discomfort symptoms, need to go to the hospital dermatology department in time.