A patch of darkened skin can be caused by sunburn, post-inflammatory hyperpigmentation and seborrheic keratosis.
1. Sunburn: If part of the skin of the body is exposed to sunlight for a long time, the skin will be damaged by excessive ultraviolet rays, which will lead to localized sunburn, and then there will be a piece of darkened skin on the body.
2. Post-inflammatory hyperpigmentation: if the patient originally existed skin allergies, breakouts and inflammatory diseases such as recovery, local due to post-inflammatory hyperpigmentation will appear a piece of skin darkening.
3. Seborrheic keratosis: If the patient due to ultraviolet radiation or viral infection and other reasons caused by seborrheic keratosis, there may be a piece of the skin blackened, and preferred in the head and face and other exposed areas.
Darkening of a piece of skin may also be caused by acanthosis nigricans, etc. It is recommended that patients go to the hospital in time to clarify the cause of the disease and timely treatment to avoid further aggravation of the condition.