A Clinical and Histopathologic Study of Pityriasis Lichenoides

Kang, Byung Duk; Kye, Young Chul; Kim, Soo Nam

Abstract

BACKGROUND: Although the clinical and histopathological findings of pityriasis lichenoides(PL) are well known, there are few vailable data in Korea.
OBJECTIVE
The purpose of this study was to evaluate the clinical and histopathologic features of pityriasis lichenoides(PL). METHOD: The clinical charts, photographies and skin biopsy slides of 86 patients who had been clinically diagnosed as PL at the initial visit were reviewed. Finally 49 patients were diagnosed as PL. They were classified into 5 groups(PLA, PLA>C, PLA=C, PLC>A, and PLC) according to the distribution ratio of acute and chronic lesions, and into 3 groups(diffuse, central, and pheripheral) by Gelmetti's method. And then the evaluation of age at onset, sex distribution, form and distribution of skin lesions, associated symptoms, clinical course, response to the treatment, and histopathologic features was conducted.
RESULTS
1. PL was more common in young adults(mean age 26.6 years) and males(male : female 2.5: 1). The trunk and proximal extremities were the predilection sites but also the acral(1) and facial(2) areas were involved. There were no specific symptoms in most cases, but, mild itching sensations in 7 cases and fever in i case. 2. The clinical course in 22 followed-up patients was 25.05+/-37.51months. The acute forms (PLA, PLA>C, and PLA=C) tended to run a fairly longer course than the chronic forms(PLC >A and PLC) but the statistical significance of these difference was low. 3. Most patients were improved by oral tetracycline, topical steroid application, and UVB therapy within the range of a few weeks to several months. But in 2 cases the lesions lasted over a year. 4. The histopathologic study of both PLA and PLC revealed the perivascular lymphocytic infiltration, obscuring of the dermo-epidermal junction by lymphocytic infiltration and exocytosis. In addition to the deeper and severe lymphocytic infiltration, the findings of dyskeratosis, epidermal necrosis, intraepidermal RBC trapping, RBC extravasation in dermis and papillary dermal edema were more prominent in PLA than PLC. 5. The diseases which were chnically confused with PL included the subacute or chronic dermatitis, insect bite, drug eruption, folliculitis, pityriasis rosea, etc.
CONCLUSION
PL is an epidermal and dermal inflammatory condition that has a benign and self limited course in most cases. The classification according to the distribution ratio of acute and chronic lesions seems more useful in the evaluation of clinical type and course.