Studies - Pigmentary demarcation lines over the face

BACKGROUND: We have been observing that a significant proportion of our patients, especially females, have certain pigmentary demarcation lines (PDL) over the face. However, systematic studies of the subject are lacking.
AIMS: We categorized the different clinical patterns of facial PDLs in the Indian subpopulation and assessed their prevalence in this study.
METHODS: About 4000 consecutive patients, both males and females, attending our skin clinic were examined for the presence of any pigmentary demarcation lines on the face, from October 1998 to February 2000.
RESULTS: Out of the study population of 4037 patients, 243 (6%) were found to have demarcation lines on the face. The demarcation lines were far more common in women (9%) than in men (0.75%). These lines could be classified into three patterns that we would like to label as F, G, H as PDLs A to E have already been described.
CONCLUSIONS: Pigmentary demarcation lines are fairly common in the Indian population especially amongst the females. Hormonal influences could possibly explain the female preponderance. Aggregation of cases within families or among close relatives suggests a genetic background.