Case of the Month

A 19-year-old man comes in for the treatment of “body fungus”. He said he had done 3 sessions of Selsun Blue shampoo for the treatment of a diagnosis of ‘tinea versicolor”. He reports none of the treatments worked.

What's Your Diagnosis?

Diagnosis: Confluent and Reticulated Papillomatosis of Carteaud and Gougerot, a.k.a. “CARP”

Information from VisualDx.com

(Dr. Crutchfield is a Dermatology Editor for VisualDx.com)

Contributors: Elizabeth B. Wallace MD, Susan Burgin MD

Synopsis

Confluent and reticulated papillomatosis (also known as confluent and reticulated papillomatosis of Gougerot and Carteaud or Gougerot-Carteaud syndrome) is a rare cutaneous dermatosis of undetermined etiology with clinical features resembling acanthosis nigricans and tinea versicolor. It has been speculated that the disorder may be due to an endocrine disturbance, abnormal keratinocyte differentiation and maturation, an abnormal host reaction to bacteria or fungi, or that it may be hereditary. Onset is usually at puberty, but the age range of those affected has been reported to be from 5-63 years.

It is clinically characterized by brown, hyperkeratotic or verrucous, thin papules that usually affect the upper central trunk and axillae. These papules coalesce into reticulated plaques. The lesions are usually asymptomatic but may be pruritic. The disorder typically affects young adults. While responsive to treatment, the disease is usually chronic and marked by exacerbations and remissions.

Diagnostic criteria have been proposed by Davis et al (Ann Dermatol. 2014 Jun;26[3]:409-410) due to frequent misdiagnosis of this condition and include the following: (i) clinical findings include scaly brown macules and patches, with at least some appearing reticulated and papillomatous; (ii) involvement of the upper trunk and neck; (iii) negative fungal staining of the scales; (iv) no response to antifungal treatment; and (v) excellent response to minocycline. A second research group proposed revised criteria to include clinical involvement of the flexural areas and management with antibiotics, rather than minocycline specifically.

Treatment

There are several abx protocols used to treat CARP, found in textbooks and on the internet.

In this particular case I gave the patient minocycline, 100mg tabs, 1 P.O. BID x 2 months with complete resolution.

Also

The possibility that this is due to skin infection is supported by the success of treatment with antibiotics. Dietzia papillomatosis is the current leading infectious candidate. This is a gram-positive actinomycete that was first isolated from a patient with confluent and reticulated papillomatosis in 2005 (https://dermnetnz.org/topics/confluent-and-reticulated-papillomatosis/)