India, March 4 -- Many people have darker skin on the neck and underarms compared to other parts of the body. While this can appear to be a hygiene issue at first instance, that is not the case, as washing or scrubbing does not help the situation at all.

Taking to Instagram on March 4, Dr Kunal Sood, a Maryland-based physician in Anesthesiology and Interventional Pain Medicine, explained that the condition can be a medical sign of an underlying condition.

The name of the condition is acanthosis nigricans, shared Dr Sood. The regions where it affects, the skin "looks darker and velvety" because it is "thickening," and not because of being unclean.

"Most commonly, (the condition) is linked to high insulin levels from insulin resistance, ...