Hyperkeratosis factitia (or dermatitis factitia) is where lesions look like irritant dermatitis, but are often self-inflicted. This can be through varying ways of injuring the skin i.e. repeatedly rubbing or picking at the skin. It is commonly from low grade repeated friction.
The lesion of often in unusual shapes, with clearly demarcated edges from surrounding normal skin. They are on sites of the body that are accessible to the patient.