What is black or dark neck? It's a term used to describe a condition that leaves the skin on the neck considerably darker than the surrounding skin. The main symptoms are hyperpigmentation, thickening of the skin, and velvety patches. So, what causes it? Several conditions may cause the darkening of the neck, like drug-induced skin pigmentation, dermatitis neglecta, or obesity. The key to eliminating and preventing it is to treat the underlying condition. You should first consult your doctor to determine the most effective treatment for your skin type and condition. Treatments may include chemical peels, medications, microdermabrasion, lasers, and creams or ointments.