Loss of hair attributable either to the effects of inflammatory cells on follicles or to physiological or mechanical factors in which inflammatory cells play no role.
An inflammatory process that develops secondary to trauma, usually in the form of a penetrating injury or rupture of a follicle, and that proceeds through stages of granulation tissue with numerous extravasated erythrocytes, granulomatous inflammation, and fibrosis.
A malignant nonepithelial neoplasm (a sarcoma) presumably of perineural fibrocytes that presents itself usually on the trunk, but sometimes elsewhere, such as the extremities, face, and scalp.
A hamartoma of mostly follicular elements that presents itself clinically as a firm, skin-colored papule.
Infundibulitis, usually a suppurative inflammatory process that involves infundibula, is either noninfectious, as in the case of pustules of acne vulgaris, or infectious, as in the case of pustules caused by Staphylococcus aureus.
Malignant neoplasms of B-lymphocytes especially that present themselves usually as papules, nodules, and tumors, sometimes solitary but at other times numerous, and often in clusters on any anatomic site.
A systemic lymphoma of T-lymphocytes that manifests itself first in the skin as macules and then patches that often are scaly.
A constellation of lesions that represent disorders of melanocytes (e.g., axillary “freckles” and café au lait “spots”) and of proliferations of Schwann cells (e.g., papules, nodules, and tumors of neurofibroma).