Increased melanocyte-stimulating hormone in Cushing's syndrome leads to what skin change?

In Cushing's syndrome, there is an excess production of cortisol, which can occur due to various causes such as adrenal tumors, pituitary adenomas, or ectopic ACTH production. One of the multiple effects of excess cortisol is the stimulation of melanocyte-stimulating hormone (MSH) production.

Melanocyte-stimulating hormone plays a crucial role in regulating skin pigmentation by stimulating melanocytes to produce more melanin, the pigment responsible for coloration in the skin. In the context of Cushing’s syndrome, increased levels of MSH can lead to hyperpigmentation, which is characterized by darker patches or areas on the skin. This hyperpigmentation can manifest in various ways, often seen in areas such as the face, neck, and other sun-exposed regions, as well as in skin folds or scars.

Overall, the mechanism of increased MSH due to cortisol excess provides a pathway for the observed skin changes, specifically leading to hyperpigmentation in individuals with Cushing’s syndrome. This distinguishes it clearly from decreased pigmentation or thinning of the skin, which would not typically be associated with elevated MSH levels.