Linear lesions in dermatology: a clinicoaetiopathological study

BACKGROUND: Linear lesions are fairly common in our daily practice. However, the appearance of these lesions can vary, thus complicating the diagnosis. AIMS: To study the various clinical presentations, the demographic profile of patients and the clinicopathological correlations of dermatoses presenting with a linear distribution. METHODS: We conducted an institution-based, cross-sectional, descriptive study of 281 consecutive patients with linear lesions attending dermatology clinics. MedCalc software (V11.6) was used for statistical analysis. RESULTS: Patients were divided into eight groups: lesions along the lines of Blaschko (n = 136), lesions along blood vessels (n = 3), lesions along lymphatics (n = 3), Koebner phenomenon (n = 24), autoinoculation (n = 24), external factors (n = 45), infestations (n = 2) and 'other' (n = 44). The mean age at presentation was 24.50 ± 18.82 years and the male/female ratio was 1.32 : 1. The commonest symptom was itching/burning (56.94% of patients), while the commonest site was the arm (44.48%); followed by the leg (30.60%), trunk and abdomen (22.42%), head and neck (19.20%), and genitalia (0.35%). Apart from the common cases, there was a wide gamut of rare conditions (e.g. angiokeratoma circumscriptum naeviforme, porokeratotic eccrine ostial and dermal duct naevus, Blaschko-linear syringocystadenoma papilliferum, progressive cribriform and zosteriform hyperpigmentation, unilateral naevoid acanthosis nigricans, fixed drug eruption, discoid lupus erythematosus). CONCLUSION: Linear lesions act as diagnostic clues to many dermatological conditions, therefore, the importance of meticulous examination in clinical dermatology cannot be overemphasized.