Papillomatosis, Confluent And Reticulated
Description
Confluent and reticulated papillomatosis is a dermatologic disorder characterized by onset in the teenage or young adult years of hyperkeratotic 1- to 2-mm papules that increase in size to 4 to 5 mm and coalesce to form a reticular pattern peripherally and a confluent pattern centrally. Early papules can be erythematous and later turn brown. Affected individuals are usually otherwise asymptomatic. The condition is distinct from acanthosis nigricans and tinea versicolor (infection with the yeast Pityrosporum), but can appear similar. Microscopic examination of skin biopsy shows epidermal undulation with hyperkeratosis, squat papillomatosis, and occasional acanthotic downward projections from the bases of the dells between papillomatous areas. Antibacterial agents such as minocycline and azithromycin are effective, perhaps due to their antiinflammatory and immunomodulatory properties (summary by Scheinfeld, 2006).
Clinical FeaturesBaden (1965) described a confluent, reticular type of papillomatosis in 2 sisters and the daughter of one.
Henning and de Wit (1981) described the disorder in a 44-year-old woman and her 15-year-old daughter and 18-year-old son. The lesions became more pigmented during the premenstrual phase of the women's cycle.
Inaloz et al. (2002) reported 2 brothers, aged 27 and 21 years, with a 5- and 2-year history, respectively, of an asymptomatic scaly rash. It first appeared on the chest and progressed to the flanks and axilla of the older brother and predominantly involved the upper back of the younger brother. Affected skin had a brownish rash forming confluent plaques in the center and a reticulated network at the periphery, consistent with CARP. Immunohistochemistry of skin biopsies showed increased suprabasal keratin-16 (KRT16; 148067) expression in the epidermis with intense focal staining in the stratum granulosum, and an increased number of cycling epidermal cells in the basal layer and stratum malpighii. Electron microscopy showed an increased number of transitional cells between the stratum granulosum and stratum corneum. There was no evidence of mycologic infection. Inaloz et al. (2002) postulated a hyperproliferative keratinocyte disorder. There was no family history of a similar disorder.
Eisman and Rustin (2003) reported a sister and brother with CARP. The girl presented at age 12 years with a hyperpigmented ichthyotic rash over the upper back, upper arms, and chest. Treatment with UVB phototherapy was effective, but the condition returned with extension after treatment cessation. Treatment with minocycline was effective. Her brother had a sib-matched allogenetic bone marrow transplant from their older brother for leukemia at age 6 years. He presented at age 14 years with hyperpigmented, scaly skin lesions of the back and upper chest; treatment with minocycline was effective. Neither sib had a fungal skin infection. Eisman and Rustin (2003) supported a role for hyperkeratinization in this condition, and suggested that the benefit from minocycline may be attributed to the inhibition of rapid protein synthesis of keratinocytes.
Thoms et al. (2006) reported 2 German brothers, ages 25 and 16 years, with a several-year history of reticular hyperpigmentation that was slowly increasing. The lesions were mildly pruritic. Examination showed punctiform and verrucose brown lesions mainly on the trunk, upper arms, and buttocks. The father reportedly had similar skin lesions. Laboratory studies confirmed that both were infected with the yeast Pityrosporum orbiculare. However, biopsy showed hyperkeratosis with focal parakeratosis, as well as subtle acanthosis between the papillae. The lesions did not respond to treatment with ketoconazole, but did respond to azithromycin.