Scratching on the legs long black scars recurring situation, consider and neurodermatitis, skin allergies, psoriasis and other factors, according to the cause of the removal of triggering factors, glucocorticoids, antihistamines, etc. for relief. 1. Neurodermatitis: may cause patients to appear local itching and inflammation pigmentation caused by black scars, should reduce and remove the triggering factors, avoid the use of irritating skin care products, improve the scrubbing, hot water scalding and other behavioral patterns, at the same time with the use of topical glucocorticosteroid ointment, such as betamethasone, hydrocortisone and other treatments. 2. Skin allergy: if the patient belongs to the allergic body, there may be skin itching, and after repeated scratching, there will be localized pigmentation, and antihistamines can be chosen, such as loratadine, cetirizine, etc., to improve the localized itching. 3. Psoriasis: chronic scaly skin disease caused by a variety of roles, accompanied by the symptoms of itching, through local scratching may make the symptoms worse, and left the inflammation hyperpigmentation, manifested as local black scars over and over again and other symptoms, can be used externally with cardpo-triol ointment, vita-acid cream, hydrocortisone butyrate, and other medications for treatment. There may be other reasons for the itchy black scars on the legs, it is recommended to consult a dermatologist in a timely manner, under the guidance of the doctor to standardize the treatment. The medication should be used in accordance with the doctor’s instructions, do not self-medicate.