What to know about acanthosis nigricans in people with diabetes

The patches often appear on the back or sides of the neck, armpits, groin, or other skin folds. They may feel thicker and have a soft, velvety texture rather than looking like a simple surface stain. Acanthosis nigricans can accompany insulin resistance and may be seen alongside diabetes, but similar-looking darkening can have other causes. A clinician can distinguish it from irritation, fungal infection, medication effects, or a different pigment disorder.

The change is usually gradual and may not itch. Scrubbing does not remove it and can make the skin inflamed. Treating the underlying metabolic issue may prevent progression and can gradually improve the appearance, although the colour may not change immediately.

Arrange a review with your diabetes clinician or dermatologist, especially if the change is new or spreading. Bring a list of medicines and mention changes in thirst, urination, weight, or glucose readings. Follow your diabetes plan, take medicines as prescribed, and avoid bleaching creams, harsh scrubs, or friction in the folds unless prescribed. Keep folds gently clean and dry, and use a bland moisturiser if rubbing causes dryness.

Seek prompt medical assessment if dark, thickened skin appears suddenly, spreads quickly, involves the mouth or many areas, or comes with unexplained weight loss, marked weakness, or other new symptoms. Arrange earlier review for pain, cracking, bleeding, odour, discharge, or a rash that is warm and tender, because a fold infection may need separate treatment. Do not assume every dark patch is acanthosis nigricans.

Ask whether the appearance fits acanthosis nigricans, whether glucose or other tests need review, and whether any medicine could be contributing. Ask which skin products are safe for your folds and how long improvement might take after the underlying issue is addressed.