While bruises can turn the skin black, they seldom itch unless there is an accompanying infection. Any itching that's associated with a black bruise should be seen by a doctor to prevent the spread of an infection. More often, however, black itchy skin is associated with more serious skin conditions that require medical treatment.
The human immunodeficiency virus, more commonly known as HIV, often goes undetected until a symptom such as a persistent skin conditions appears. According to Family Doctor, the sudden appearance of black raised itchy spots on the skin could indicate the presence of kaposis sarcoma, a skin cancer common to people with HIV. The appearance of the black spots may lead to early detection of the virus, which usually responds well to early diagnosis and treatment.
When too much insulin remains in the blood for long periods of time, complications can occur that affect the skin. According to the National Diabetes Information Clearinghouse, in addition to consequences such as blindness and heart attacks, high blood sugar levels can cause poor circulation and nerve damage to the feet, causing them to turn black.
Initially poor blood flow appears in the form of blisters, which then can become infected. The extra blood sugar in the body feeds the infection that exacerbates the condition. The infection may not heal because of the poor circulation in the legs. The skin around the infection then dies and turns black and itchy, indicating gangrene. Once gangrene has set in, the foot or toes that are black must be amputated to prevent the infection from spreading.
Dark brown and black spots common with aging have the potential to turn into more serious conditions. According to the American Academy of Dermatology, you should monitor the black spots for changes or itchiness that could indicate skin cancer. If detected early, freezing them off or using a resurfacing procedure can remove the spots. Malignant melanomas are itchy black spots that are more common in men and tend to appear on the backs of the hands, face or neck. Left untreated, the cancer can spread to other parts of the body and prove fatal.
Dark itchy spots on the vulva can indicate an infection that should be treated. The vulva is the fleshy outside skin around the vagina. According to the American Congress of Obstetricians and Gynecologists, the black itchy spots can result from a yeast infection, cancer, a sexually transmitted disease or contact dermatitis. Vulvar cancers mostly affect women over the age of 60 and usually are treated with surgery. Prevention can help you avoid other vulvar infections. Common preventive measures include not wearing tight pants, keeping the area clean and dry and avoiding douches.