Ostiofolliculitis and folliculitis

Ostiofolliculitis or staphylococcal impetigo (syn.: Bockhard's impetigo) is an acute inflammation of the mouth of the hair follicle caused by staphylococcus. On the skin of hairy areas, most often the face and head, there appear single or multiple, conical or hemispherical pustules the size of a pinhead, located at the mouths of the hair follicles, often pierced in the center by a hair, filled with thick pus, surrounded by a small halo of hyperemia. After a few days, the contents of the pustule dry out with the formation of a brownish crust.

Pathomorphology of ostiofolliculitis or staphylococcal impetigo

The pustule is located under the stratum corneum of the epidermis, surrounding the opening of the hair follicle. Over time, purulent melting of this part of the follicle occurs. An inflammatory infiltrate is detected in the dermis, localized around the upper part of the epithelial hair follicles. The infiltrate consists mainly of a large number of neutrophilic granulocytes.

Folliculitis is a purulent inflammation of the hair follicle, most often caused by Staphylococcus aureus. It usually develops from ostiofolliculitis, clinically it is a small conical pustule, pierced in the center by vellus hair. After the folliculitis opens and pus is released, a small ulcer remains, which is covered with a purulent-bloody crust, which subsequently falls off with the formation of a pigment spot or scar. Elements can be single or multiple.

Pathomorphology

An accumulation of pus is found in the hair follicle, and an infiltrate consisting of leukocytes and lymphocytes is found in the perifollicular tissue.