The calluses are circumscribed, horny, conical thickenings that have their base on the surface and their tip pointing inward and pressing on the subjacent structures. Callus differs from clavus (clavus does not have a penetrant central nucleus and is a more diffuse thickening).

Onychomycosis is a contagious infection and is divided into the following types:

Peripheral onychomycosis, which affects the free edge of the nail but also the hyponychium, white superficial onychomycosis which affects the surface of the nail and total onychomycosis.

Diarrhea is not a disease but a symptom, it is a reaction of the body to a bowel disorder. The cenosis show differentiations from normal with the most common being increase in number, size but also in fluidity.