Acanthosis nigricans

Acanthosis nigricans is a skin condition characterized by areas of darkened, thickened, and velvety skin, usually found in body folds such as the neck, armpits, and groin. It primarily affects the skin system and is often a visible sign of an underlying health issue. The condition is commonly associated with insulin resistance, which can occur in diseases like type 2 diabetes or obesity. Sometimes, it may indicate more serious problems such as hormonal disorders or even cancer. The affected skin areas may feel rough or have a slightly raised texture but usually do not cause pain or itching. Recognizing these skin changes can help identify underlying metabolic or systemic conditions.

Acanthosis nigricans is a dermatologic disorder characterized by hyperpigmented, hyperkeratotic, and papillomatous plaques predominantly affecting intertriginous areas. The core pathology involves epidermal hyperplasia and increased melanin deposition in the basal layer. It is most commonly caused by hyperinsulinemia-induced activation of insulin-like growth factor receptors on keratinocytes and dermal fibroblasts, leading to epidermal proliferation. This condition serves as a clinical marker for insulin resistance syndromes, including type 2 diabetes mellitus and obesity. Less commonly, it may be a paraneoplastic phenomenon associated with gastric adenocarcinoma or other malignancies. Recognition of acanthosis nigricans is important for early detection of underlying endocrine or neoplastic disorders.