Aacanthosis Nigricans is a condition which is Insulin resistance stage. This needs  1.Hormonal check, blood test work ups, 2 pigmentation management with local creams and treatments prescribed by dermatologist , and lifestyle management. Of weightloss, exercise, meditation, stress relieving , and diet management. It is a lifestyle disease leading to multiple issues.

Acanthosis nigricans is a metabolic disorder in which there is insulin resistance due to overweight and that leads to accumulation of excessive skin or increase thickness of the skin on soft part like neck and resulting in dirty neck appearance or pigmented neck or underarms. Main treatment for acanthosis nigricans is weight control and along with that there are so many topical solutions which are beneficial like Urea Lactic acid cream, salicylic acid, even depigmentation agents like cogic acid, arbutin, chemical peels with Glyolic acid. You need to visit dermatologist personally for exact treatment depending on the condition