GP Quiz 4 - Case 2.
This lady weighs 90 kg. She requests help lightening the colour of her neck.
What is this condition?
This is acanthosis nigricans.
What other areas should be examined?
The entire skin, but particularly the flexures (groin, axillae) and dorsa of fingers. Look for hyperpigmented velvety plaques and skin tags. Examine for associated systemic diseases.
What is the cause?
Acanthosis nigricans is due to insulin resistance.
With what conditions is it associated?
The commonest associated disorder is obesity. Endocrine associations include diabetes mellitus, hypothyroidism, and polycystic ovaries. Paraneoplastic associations include adenocarcinoma of the stomach, and malignancies of small and large bowel, ovaries, lung, breast and prostate. Drug-induced acanthosis has occurred with nicotinic acid, oestrogens and corticosteroids.
Is there any useful treatment?
Treatment is disappointing. The acanthosis may remit with successful treatment of underlying disease.
This quiz was originally published by ADIS International in April 1998