There is a black spot on the calf sometimes itchy may be contact dermatitis, varicose veins, nevus and other factors, the patient should consult a doctor in time, clear cause of the disease after treatment. 1. contact dermatitis: if the patient has black spots on the legs and sometimes itchy before contact with pollen and other substances, and itching and burning sensation, it should be considered contact dermatitis caused by such people should be detached from the allergen, under the guidance of the doctor to use loratadine and other drugs for treatment. 2. Varicose veins: varicose veins of the lower limbs refers to the superficial veins of the lower limbs that are localized into clusters, and the patients will have black spots with itching due to hyperpigmentation, as well as skin atrophy and local ulcers, which can be relieved through surgery under the guidance of doctors. 3. Nevus pigmentosus: a benign tumor formed due to the proliferation of melanocytes, when it occurs on the calf, it can be manifested as itchy black spots, usually no special treatment is needed, and it can be surgically excised under the guidance of the doctor when needed. If the above symptoms occur, it is recommended to go to the hospital in time for early and regular treatment.