[Lichen nitidus: favorable response of 2 cases to narrow-band UV-B phototherapy].

Lichen nitidus (LN) is a rare, chronic, and usually asymptomatic inflammatory disease characterized by numerous small, well-defined, flesh-colored papules.1 The lesions tend to be localized, and most commonly affect the abdomen, chest, genitalia, flexor areas of the arms, or backs of the hands, but can become generalized in rare cases. As LN is usually asymptomatic and tends to resolve spontaneously in 1 or more years, it rarely requires treatment. However, generalized LN presents a much more unpredictable clinical course and is more frequently associated with itching2; it therefore requires treatment. We describe 2 patients with generalized LN whose lesions responded rapidly to phototherapy with narrow-band UV-B. Two women aged 48 and 22 presented a pruritic rash from 7 years and 10 months previously, respectively, consisting of small, shiny, flesh-colored papules with a generalized distribution affecting the breasts, neck, trunk, back, upper limbs, and thighs (Figure 1). The patients had been clinically diagnosed with eczema and unsuccessfully treated with topical corticosteroids. In both cases, the biopsies showed identical findings consisting of a well-circumscribed subepidermal granulomatous infiltrate composed of lymphocytes and epithelioid cells, delimited by 2 elongated papillary ridges (Figure 2). Once lichen nitidus was diagnosed, narrow-band UV-B phototherapy consisting of 3 sessions per week was initiated. In both patients, the initial dose was 0.15 J/cm2, and a favorable response was observed after only 4 and 5 sessions, respectively. The lesions resolved almost entirely after 18 and 12 sessions (Figure 3) and a cumulative dose of 4.41 J/cm2 and 3.59 J/cm2, respectively. Both patients remained lesion-free after a follow-up of 6 months and 1 year, respectively. Treatment for LN is indicated in persistent, generalized cases when the lesions are cosmetically unacceptable or accompanied by symptoms, such as itching.3 Various treatments have been used for the condition: topical and oral corticosteroids, antihistamines (astemizole), acitretin, low-dose ciclosporin,6 itraconazole,7 isoniazid,8 dinitrochlorobenzene immunotherapy,9 and ultraviolet phototherapy. In the case of LN treatment with ultraviolet radiation, there are isolated case reports of a favorable response to oral psoralen-UV-A (PUVA),3 UV-B/UV-A phototherapy associated with low-dose corticosteroids,10 and intense exposure to solar UV radiation.2 Figure 1 Patient 1: Typical lichen nitidus lesions (small leshy papules on the abdomen) before treatment.