<unk>  is a long-lasting, usually painless ulcer that penetrates deep into or through the skin, usually on the sole of the foot (in which case it may be called<unk>  pedis). It is often a complication in diabetes mellitus and other conditions affecting the nerves.
Malum perforans
Lichen spinulosus
Lichen aureus
Lichen ruber moniliformis
Herpes gladiatorum
Ichthyosis hystrix
Tinea incognita
Lawsonia inermis