CLINICAL MICROBIOLOGY REVIEWS, Apr. 1995, p. 240–259 Vol. 8, No. 2 0893-8512/95/$04.0010 Copyright q 1995, American Society for Microbiology The Dermatophytes 1 2 IRENE WEITZMAN * AND RICHARD C. SUMMERBELL Clinical Microbiology Service, Columbia Presbyterian Medical Center, New York, New York 10032-3784,1 and Mycology Laboratory, Laboratory Services Branch, Ontario Ministry of Health, Toronto, Ontario M5W 1R5, Canada2 INTRODUCTION .......................................................................................................................................................240 HISTORICAL REVIEW.............................................................................................................................................241 ETIOLOGIC AGENTS...............................................................................................................................................241 Anamorphs...............................................................................................................................................................241 Epidermophyton spp. ...........................................................................................................................................241 Microsporum spp. ................................................................................................................................................241 Trichophyton spp. ................................................................................................................................................241 Teleomorphs ............................................................................................................................................................242 EPIDEMIOLOGY AND ECOLOGY........................................................................................................................242 CLINICAL MANIFESTATIONS ..............................................................................................................................244 Tinea Barbae ...........................................................................................................................................................244 Tinea Capitis ...........................................................................................................................................................244 Tinea Corporis ........................................................................................................................................................244 Tinea Cruris (‘‘Jock Itch’’)....................................................................................................................................244 Tinea Favosa............................................................................................................................................................245 Tinea Imbricata.......................................................................................................................................................245 Tinea Manuum........................................................................................................................................................245 Tinea Pedis (‘‘Athlete’s Foot’’)..............................................................................................................................245 Tinea Unguium........................................................................................................................................................245 LABORATORY DIAGNOSIS....................................................................................................................................245 Collection and Transport of Specimens ..............................................................................................................245 Microscopic Examination and Culture................................................................................................................245 Identification Characters and Diagnostic Media ...............................................................................................246 IMMUNOLOGY..........................................................................................................................................................247 PREVENTION AND CONTROL..............................................................................................................................248 PHYSIOLOGY ............................................................................................................................................................249 HISTOPATHOLOGY .................................................................................................................................................250 THERAPY ....................................................................................................................................................................251 Tinea Capitis ...........................................................................................................................................................251 Tinea Barbae ...........................................................................................................................................................251 Tinea Corporis ........................................................................................................................................................251 Tinea Cruris ............................................................................................................................................................251 Tinea Pedis ..............................................................................................................................................................251 Tinea Unguium........................................................................................................................................................252 GENETICS ..................................................................................................................................................................252 Heterothallism.........................................................................................................................................................252 Pleomorphism..........................................................................................................................................................252 Virulence ..................................................................................................................................................................252 Griseofulvin Resistance..........................................................................................................................................252 Pigmentation in A. benhamiae ...............................................................................................................................253 MOLECULAR BIOLOGY .........................................................................................................................................253 FUTURE PROSPECTS..............................................................................................................................................254 ACKNOWLEDGMENT..............................................................................................................................................254 REFERENCES ............................................................................................................................................................254 INTRODUCTION dermatophytosis, commonly referred to as ringworm. Infection is generally cutaneous and restricted to the nonliving cornified The dermatophytes are a group of closely related fungi that layers because of the inability of the fungi to penetrate the have the capacity to invade keratinized tissue (skin, hair, and deeper tissues or organs of immunocompetent hosts (57, 140). nails) of humans and other animals to produce an infection, Reactions to a dermatophyte infection may range from mild to severe as a consequence of the host’s reactions to the meta- bolic products of the fungus, the virulence of the infecting * Corresponding author. Phone: (212) 305-9377. Fax: (212) 305- strain or species, the anatomic location of the infection, and 8971. local environmental factors. 240 VOL. 8, 1995 THE DERMATOPHYTES 241 HISTORICAL REVIEW Trichophyton (Keratinomyces) ajelloi in 1959 by Dawson and Gentles (52), using the hair bait technique of Vanbreuseghem Historically, medical mycology, specifically relating to hu- (255), led to the rapid discoveries of the teleomorphs of many man disease, began with the discovery of the fungal etiology of dermatophytes and related keratinophilic fungi. Griffin in 1960 favus and centered around three European physicians in the (84) and Stockdale in 1961 (231) and 1963 (232) independently mid-19th century: Robert Remak, Johann L. Scho¨nlein, and obtained the teleomorphs of the Microsporum gypseum com- David Gruby. Details regarding their lives, specific achieve- plex, thereby vindicating Nannizzi’s original observation. ments, and historical background may be found in several The discovery of sexual reproduction in the dermatophytes excellent reviews (4, 10, 141, 217, 283). opened the door to classical genetic studies with these fungi, According to Seeliger (217), Remak in 1835 first observed e.g., determining the cause of pleomorphism