Acquired ichthyosis?

Pigmentation disorder

Dr. Emmanuelle Bourrat

Saint-Louis Hospital

The clinical case
Now it's your turn!
Co-prescription and advice

Clinical case presentation

A 13-year-old, well-adjusted, overweight teenager (74 kg for 169 cm) had been experiencing skin changes for the past two years. The discomfort was purely cosmetic with no functional repercussions. Hyperpigmentation and a rough appearance of the skin appeared at the time of puberty, initially localized to the trunk, then progressively extending to all four limbs.

The face, hands and feet were spared, although there was acanthosis nigricans of the large folds. There was no acne or hirsutism. Lesions did not disappear after rubbing with an alcohol-soaked compress.

Applications of dermo-cosmetics or keratolytics were ineffective. An endocrine workup ruled out dysthyroidism and acromegaly but revealed marked hyperinsulinemia without diabetes or polycystic ovaries.

Your turn

What is your diagnosis?

Select 1 answer(s) from the following choices:

Confluent and reticulated papillomatosis of Gougerot and Carteaud

Late-onset inherited ichthyosis

Paraneoplastic diffuse acanthosis nigricans

Terra firma-forme dermatosis

Wrong answer!

Good answer!

Selected diagnosis

This is a confluent and reticulated papillomatosis of Gougerot-Carteaud (GC), notable for its highly diffuse nature.

This rare adolescent dermatosis shares with acanthosis nigricans a pigmented, papillomatous appearance and comparable lesion histology, but differs in being more keratotic than velvety, reticulated and truncular in topography outside the folds.

Some authors consider acanthosis nigricans to be a localized form of Gougerot-Carteaud, and the association of the two dermatoses is not uncommon in the context of overweight and hyperinsulinism. However, the near-constant efficacy of antibiotics such as cyclines concerns only GC, for which it constitutes a genuine diagnostic criterion. This suggests a link with the cutaneous microbial flora, in particular the role of certain anaerobes, but this has not yet been confirmed.

Explanation of wrong answers

Hereditary ichthyosis (single-gene disease) may not be congenital, i.e. present at birth but appearing in infancy (in the case of X-linked ichthyosis and ichthyosis vulgaris) but never after adolescence.
When acanthosis nigricans is monogenic or paraneoplastic, it may occur not only outside the folds but also spread to the entire integument or even to the mucous membranes. This is a diagnosis that could have been considered here on the basis of semiology, but it was not very compatible with the context of this patient (normal height, overweight).
The lesions did not go away after rubbing with an alcohol-soaked compress, ruling out terra firma-forme dermatosis, the elementary lesion of which is very similar to that of confluent and reticulated papillomatosis.

Treatment

A trial treatment with cyclines for 2 months resulted in a significant regression of the diffuse pigmented plaques, confirming our diagnostic hypothesis.

Message from the expert

Gougerot-Carteaud’s confluent and reticulated papillomatosis should be suspected not only in the presence of pigmented pityriasis versicolor resistant to antifungal treatment but also in the presence of diffuse acanthosis nigricans or acquired ichthyosis. A trial treatment with oral cyclines is an authentic diagnostic test.

References :

^{M.D.P. Davis et al.}^{Confluent and reticulate papillomatosis, British Journal of Dermatology 2006 154, pp287-293}