Identify this Skin Pathology:
A. Lichen Planus
- Psoriasis is a chronic inflammatory dermatosis.
- The lesions are characterised by brownish-red papules and plaques which are sharply demarcated and are covered with fine, silvery white scales.
- As the scales are removed by gentle scrapping, fine bleeding points appear termed Auspitz sign.
- Commonly involved sites are the scalp, upper back, sacral region and extensor surfaces of the extremities, especially the knees and elbows. In about 25% of cases, peculiar pitting of nails is seen.
- Histologically, the following features are observed in fully-developed lesions :
- Acanthosis with regular downgrowth of rete ridges to almost the same dermal level with thickening of their lower portion.
- Elongation and oedema of the dermal papillae with broadening of their tips.
- Suprapapillary thinning of stratum malpighii.
- Absence of granular cell layer.
- Prominent parakeratosis.
- Presence of Munro microabscesses in the parakeratotic horny layer is diagnostic of psoriasis.