Disease secondary to rubbing and/or scratching
Lichen simplex chronics/ Prurigo nodularis/ Picker's nodule/ Erosion/ Ulcer
Fully developed
Epidermal type:
| Extensive compact orthokeratosis that resembles the normal stratum granulosum on a palm or sole |
| Prominent hypergranulosis that resembles the normal stratum granulosum on a palm or sole |
| Spinous cell hyperplasia |
| Follicles present in the section |
Epidermal and dermal type:
| Compact orthokeratosis sometimes with focal parakeratosis; scale-crusts, and erosions if scratching accompanies rubbing |
| Ostia of infundibula and eccrine ducts often dilated by cornified cells arranged compactly |
| Hypergranulosis, especially prominent in acrotrichia and acrosyringia |
| Uneven psoriasiform hyperplasia |
| Papillary dermis thickened by coarse bundles of collagen in vertical streaks |
| Dilated capillaries in the thickened papillary dermis in vertical array, i.e., parallel to the bundles of collagen in vertical streaks |
| Increased number of fibrocytes, some binucleate and others mulinucleate, with abundant stellate cytoplasm in a thickened papillary dermis |
| Superficial perivascular infiltrate of lymphocytes, occasional plasma cells, and histiocytes, with melanophages among them ranging from sparse to moderately dense; often no infiltrate of inflammatory cell |