Dermatology Online Journal

Confluent and Reticulate Papillomatosis
Jashin J Wu MD, Boris H Borazjani MD, Jeffrey V Benabio MD, Edward W Jeffes 3rd MD PhD, Senait W Dyson MD
Dermatology Online Journal 14 (3): 10

Department of Dermatology, University of California, Irvine, Irvine, CA. jashinwu@hotmail.com

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Abstract

A 24-year-old man had an asymptomatic rash on his chest and arms for one year. On his chest, there were brown confluent plaques in a reticulate pattern. A scraping for fungus was negative. A biopsy showed papillomatosis, orthokeratosis, and melanin pigment at the basal layer of the epidermis. The patient was started on a six-week course of minocycline twice/day. Six weeks later, the patient was completely clear of the rash. Confluent and reticulate papillomatosis is an uncommon dermatosis that tends to occur on the chest. The pathogenesis is unknown. Minocycline has been reported to work well in the treatment of this dermatosis.

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Case Report

A 24-year-old male war veteran presented with a one-year history of a rash on his chest and arms. Skin examination revealed brown confluent plaques in a reticulate pattern (Fig. 1). He denied any symptoms and had not been treated. His past medical history was significant for gastroesophageal reflux disease for which he was treated with omeprazole.

Figure 1	Figure 2
Figure 1. Brown confluent plaques in a reticulate pattern on the chest Figure 2. Skin biopsy findings showed orthokeratosis, papillomatosis, slight acanthosis and the presence of melanin pigment at the basal layer of the epidermis (hemotoxylin and eosin, original magnification x 10).

The results of routine laboratory investigations were within normal limits. No fungus was found on potassium hydroxide (KOH) examination. Bacterial and fungal cultures were negative. A scalpel biopsy was obtained from the left arm (Fig. 2). The skin biopsy showed orthokeratosis, papillomatosis, slight acanthosis, and the presence of melanin pigment at the basal layer of the epidermis.

The patient was treated with a six-week course of minocycline twice/day, and he noticed that the rash was fading one week after starting the regimen. On his six-week follow-up, the patient's rash was completely clear. He did not require further treatment. The patient was lost to follow-up after this appointment.

Confluent and reticulate papillomatosis (CARP) is an uncommon dermatosis, first reported by Gougerot and Carteaud [1]. Classically lesions appear as persistent papules that are confluent in the center and reticulate at the periphery. The sites of predilection are the interscapular region, neck, inframammary area and abdomen [2]. These lesions are typically asymptomatic, but pruritus may occasionally occur [3]. Confluent and reticulate papillomatosis usually occurs in the second or third decades of life [4]. The majority of cases are sporadic, although familial cases have been reported. The pathogenesis of CARP is poorly understood. Possible proposed causes of CARP include endocrine abnormalities, disorder of keratinization, abnormal response to fungi, exposure to ultraviolet light, and hereditary predisposition.

The differential diagnosis of CARP includes Darier's disease, acanthosis nigricans, pseudoacanthosis nigricans, prurigo pigmentosa, tinea versicolor [5], eczematous dermatitis, seborrheic dermatitis, and photodermatitis [6].

Confluent and reticulate papillomatosis may be resistant to therapy. The topical treatment of CARP is variably effective and lesions recur often, requiring systemic treatment. Various antibiotics, with minocycline in particular, have been reported for the treatment of CARP with good results [7]. Treatment with oral retinoids, phototherapy, radiotherapy, cryotherapy and dermabrasion has also been reported with varied results [2].

References

1. Gougerot H CA. Papillomatosis pigmentee innominee. Bull Soc Fr Dermatol Syph 1927:719-21. (No PMID)

2. Bowman PH, Davis LS. Confluent and reticulate papillomatosis: response to tazarotene. J Am Acad Dematol 2003:S80-1. PubMed

3. Barnette DJ Jr, Yeager JK. A progressive asymptomatic hyperpigmented papular eruption. Confluent and reticulate papillomatosis of Gougerot and Carteaud. Arch Dematol 1993:1608-9. PubMed

4. Lee MP, Stiller MJ, McClain SA, Shupack JL, Cohen DE. Confluent and reticulate papillomatosis: response to high oral isotretinoin therapy and reassessment of epidemiological data. J Am Acad Dematol 1994:327-31. PubMed

5. Sau P, Lupton GP. reticulate truncal pigmentation. Confluent and reticulate papillomatosis of Gougerot and Carteaud. Arch Dematol 1988:1272-5. PubMed

6. Mutasim DF. Confluent and reticulate papillomatosis. J Am Acad Dematol 2003:1182-4. PubMed

7. Jang HS, Oh CK, Cha JH, Cho SH, Kwon KS. Six cases of confluent and reticulate papillomatosis alleviated by various antibiotics. J Am Acad Dematol 2001:652-5. PubMed

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