Solar radiation heats up rather the body's surface and not the interior. She also found that folate was crucial to sperm development; some male contraception drugs are based on folate inhibition. Log in with your Medical News Today account to create or edit your custom homepage, catch-up on your opinions notifications and set your newsletter preferences. Erythema dyschromicum perstans, or ashy dermatosis, causes slate-gray, dark blue, or black irregularly-shaped patches of skin on the neck and upper arms. As a consequence of vitamin D deficiency, they are at a higher risk of developing ricketsand numerous types of cancers, and possibly cardiovascular disease and low immune system activity.
Patches can sometimes appear on the torso.
Causes and treatment of a black neck