Multiple lichen striatus-An unusual presentation

Introduction

The history of lichen striatus dates back to the 19th century and the disease has been described repeatedly under different names due to its linear distribution, viz. linear neurodermatitis, linear dermatoses, lichenoid eruption and zonal dermatosis.[1] Lichen striatus is a self remitting inflammatory dematosis that ocurs most often in children.[2] Lesions consist of erythematous often flat topped, small papules coalescing into plaques following Blaschko′s lines. Lesions are usually asymptomatic, pruritus being a rare complaint.

We report here two cases where the patients had multiple lesions with a bilateral distribution along the lines of Blaschko.

Case 1:

A two-year-old male child presented with asymptomatic, flat topped, hypopigmented, 1 mm sized closely grouped papules arranged linearly along the lateral side of right leg from the knee to the iliac crest. Similar papuies were arranged in a whorled pattern on the right side of chest extending to the back and also on the left shoulder extending on to the front of the chest.

Case 2:

A seven-year-old girl presented with asymptomatic, hypopigmented macules of size ranging from 0.5mm-lcm arranged linearly along the left upper limb involving the arm and the forearm and lower limb extending from the thigh to the ankle. Similar lesions were present on the back arranged along the lines of Blaschko.

No other family members in both the cases had history of similar lesions. The developmental milestones were normal and the general physical examination and examination of other systems did not reveal any abnormality. On routine investigation, haemogram, blood chemistry, urine and stool examination were within normal limits. Histopathology of case 1 showed mild acanthosis, spongiosis and a lichenoid mononuclear infiltrate at the dermoepidermal junction. Histopathology of case 2 showed nonspecific chronic inflammatory infiltrate.

Discussion

There are convincing data in the literature[3] that the lesions of lichen striatus clearly follow a linear distribution in a (non metameric) dermatomal pattern. We made a diagnosis of lichen striatus on the basis of clinical morphology of linear papules arranged in a whorled pattern. These features were later corroborated with the histopathological findings. Lichen striatus usually presents as a single linear lesion. In a review of 25 cases[4] all the patients had single lesions confined to one anatomical region or extending into a contiguous area. Three discrete lines in three distinct anatomical areas in a case of lichen striatus do not appear to have been described.

Lichen striatus is one of the dematoses that follow Blaschko′s lines. The development of disease in this pattern has been ascribed to somatic mutation leading to an abnormal clone of cells. It would appear that somatic mutation occurred in three different precursor cells in our patients leading to three abnormal clones of cells and three lesions of lichen striatus.