What Is Granulomatous Dermatitis?
Unlike the term dermatitis as used by dermatology practitioners and dermatopathologists (referring to superficial skin pathology involving the epidermis and papillary dermis), the use of the term dermatitis in “granulomatous dermatitis” is loose and simply refers to a process in the skin in which the infiltrate is granulomatous, that is primarily histiocytic.
Granulomas are further divided etiologically into: infectious, inflammatory, and foreign body granulomas; and divided histologically into: sarcoidal, tuberculoid, palisading, and suppurative granulomas, with overlap.
The differential diagnosis of granulomatous dermal inflammation is wide and is classified both by etiology and pattern of infiltrate. In cases that cannot be confirmed on histological evaluation alone, special stains for organisms and polarization for some foreign bodies as well as cultures are indicated.