Linear lesions in dermatology: a clinicoaetiopathological study

Summary 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.