Dermoscopic features in Lichen planus:
- The most characteristic feature of lichen planus seen in dermoscopy is Wickham striae which histopathologically corresponds to hypergranulosis.
- They appear typically white in colour but may also appear blue in dark skinned people.
- Various morphologies of wickham striae are seen – like leaf venation, radial, linear, globular etc.,
But white structures in a net like pattern can also be seen in scarring or resolving lesions of other skin conditions like DLE, prurigo nodularis – called as Pseudo Wickham striae. It is due to dermal fibrosis.
- This pseudo wickham striae can be differentiated from the wickham striae seen in Lichen planus by the vascular morphology – the vessels appear more dilated in pseudo WS than those seen in WS
Other findings in active lesions:
- Dotted or globular or linear vessels mainly detected on the periphery of the lesions
- White/yellow dots
- pigmentary structures
The dermoscopic patterns in lichen planus differs according to the stage of the condition –
- The early popular lesions show only faintly visible WS over a red background.
- In later stages of the disease, the mature lesions show well formed WS and peripherally distributed vessels.
- In the more chronic lesions – often only pigmentary structures are seen.
Hypertrophic Lichen planus:
- Shows follicular keratotic plugging
- WS are not seen often
- Comedo like openings