A healthy 17-year-old boy presents to clinic with a gradually progressive reticulated hyperpigmentation of the chest and back, which has been present for 1 year. It does not itch or hurt and had a gradual onset. He was previously told it was tinea versicolor, but antifungal treatments did not lead to resolution.
Physical exam demonstrates a hyperpigmented, slightly scaling plaque, which is confluent centrally on the mid back and central chest (see Figure 1). Laterally and in the antecubital fossae, similar plaques are noted in a reticulated pattern. Potassium hydroxide preparation fails to demonstrate fungal elements.
Figure 1 . Chest of patient with centrally located confluent, hyperpigmented, and velvety plaque. Similar papules are at the periphery in a reticulated distribution.
Confluent and reticulated papillomatosis
Confluent and reticulated papillomatosis (CRP) of Gougerot and Carteaud is a disorder of uncertain etiology characterized in the medical literature by multiple small case series. It occurs most often in the second decade of life and presents with asymptomatic to mildly pruritic, velvety, reticulated, hyperpigmented plaques over the upper trunk, axillae, and neck. Frequently, the disease is not recognized, and diagnosis is delayed. Although of mainly cosmetic significance, it often responds very well to oral antibiotics.
CRP often begins with small 1- to 2-mm hyperpigmented and slightly hyperkeratotic papules. Occasionally, these can be erythematous. These papules increase in size and develop a papillomatosis appearance. Papules coalesce most prominently on the central and upper back, axillae, neck, and breast. As the papules coalesce, a velvety appearance similar to acanthosis nigricans is often observed. Many variants have been described including CRP without papillomatosis or hyperpigmentation. At times, patients have involvement of the forehead, lateral face, and antecubital fossae (see Figure 2).
The epidemiology of CRP is not well defined. A recent case series from the Mayo Clinic of 39 patients demonstrated an average age at presentation of 15 years.1 At the first visit, the eruption had been present for a mean of 3.1 years. Seventy-eight percent of patients had a complete response to minocycline, and the rest had greater than 50% clearance. Twenty-two percent had recurrence. CRP appeared equally common in boys and girls. There was no clear racial association. It is likely that the majority of cases of CRP go undiagnosed.
Figure 2. Reticulated, velvety, and hyperpigmented papules in the antecubital fossa.
It is important to differentiate CRP from more common conditions with similar appearances, such as acanthosis nigricans, tinea versicolor, and retention hyperkeratosis. Acanthosis nigricans is present on the neck, axillae, and groin but does not respond to antibiotics. It often lacks involvement of the central trunk and lacks a peripheral reticulated configuration. Tinea versicolor is less palpable and tends not to coalesce. In addition, potassium hydroxide preparations will demonstrate classic findings of the etiologic agent malessezia. Unlike CRP, retention hyperkeratosis can be removed with an alcohol swab.
The most effective treatment for CRP is oral antibiotics. The strongest evidence in the form of case reports is for azithromycin or minocycline. A case series of 1 1 patients with CRP treated with minocycline 50 mg orally twice per day for 6 weeks led to a complete response in nine of the 1 1 patients.2 Recurrences occurred in three patients, who responded to another course of therapy. Numerous case reports have shown the effectiveness of azithromycin, which is in agreement with our experience. Other oral therapies include clarithromycin, tetracycline, furacycline, azfuracycline, and cefdinir.3 Because of potential adverse reactions reported for minocycline, including pseudotumor cerebri, lupus-like syndrome, and autoimmune hepatitis, and the possibility of recurrences, our first-line therapy in children is azithromycin for 5 days every 2 weeks until resolution. CRP often resolves after a single course; however, some patients may require three to four courses.
Retinoids have also been found to be useful in CRP. Topical tazarotene (Tazorac) and tretinoin (Retin-A) have been reported to be effective, but they can be difficult to apply to central mid-back. Oral retinoids such as isotretinoin (Accutane) or acetretin (Sonatane) can also be effective but have undesirable side effect profiles for a relatively benign process with safer treatment approaches.
The etiology of CRP is unclear. Initially, it was thought to be caused by malessezia, the same fungal organism that causes tinea versicolor. There is increasing evidence that CRP is not related to this ubiquitous yeast, including that CRP is not responsive to topical antifungal treatment. The patients from early reports who responded to antifungal treatment likely were misdiagnosed.
A bacterial origin is possible, as CRP responds well to multiple antibiotics. However, organisms are not seen on routine skin biopsies. Several organisms have been grown from skin scrapings, but no consistent trend has been observed to date.4 A disorder of keratinization, or of skin differentiation and maturation, is also a strong possibility. The skin biopsy of CRP demonstrates changes suggestive of keratinocyte malfunction, including increased lamellar granules in the stratum granulosum and increased involucrin expression. CRP also responds to retinoids and vitamin D derivates which are treatments for other disorders of keratinization.
CRP is an idiopathic and asymptomatic eruption of the torso and upper extremities with characteristic clinical findings. The condition can cause significant psychosocial distress in teenagers because of its appearance. Oral antibiotics arc an effective treatment approach with timely resolution.
1. Davis MD, Weenig RH, Camilleri MJ. Confluent and reticulate papillomatosis (GougerotCarteaud syndrome): a minocycline-responsive dermatosis without evidence for yeast in pathogenesis - a study of 39 patients and a proposal of diagnostic criteria. Br J Dermatol. 2006;154(2):287-293.
2. Montemarano AD, Hengge M, Sau P, Welch M. Confluent and reticulated papillomatosis: response to minocycline. J Am Acad Dermatol. 1996:34(2 Pt l):253-256.
3. Jang HS, Oh CK, Cha JH, Cho SH, Kwon KS. Six cases of confluent and reticulated papillomatosis alleviated by various antibiotics. J Am Acad Dermatol. 2001;44(4):652-655.
4. Carrozzo AM, Gatti S, Ferranti G, Primavera G, Vidolin AP, Nini G. Calcipotriol treatment of confluent and reticulated papillomatosis (Gougerot-Carteaud syndrome). J Eur Acad Dermatol Venereol. 2000; 1 4(2): 131-133.