162 INFECTIONS CAUSED BY MOLDS 



3. Colonies yellowish brown with abundant aerial mycelium and very numer- 

 ous macroconidia. Microsporum' gijpseum 



4. Colonies glabrous, wrinkled, reddish violet. 



Trichophyton violaceum 

 B. No scutula present. Hairs tend to break off square. 



1. Suppurative reactions (as follicular abscesses), pustules (of kerion) absent 

 (except Microsporum species of animal origin). 



a. Hairs broken off at a uniform height, several millimeters above the skin. 

 Much scahng of the epidermis, highly contagious in most cases. Spores 

 on outside of hairs, angular, forming a mosaic. In cultures many spindle- 

 shaped macroconidia with thick, usually rough walls, multicellular (ex- 

 cept M. Audouini). Microsporum 



b. Hairs mostly broken off flush with the skin, leaving black points. Little 

 scaling of the epidermis. Not so contagious. In cultm-es conidia varia- 

 ble in size, macroconidia very few or lacking. 



aa. Grows entirely within the hair, both mycelium and spores. 



Endothrix Trichophyton 

 bb. Grows mainly within the hair, but a few hyphae and spores can be 

 found on the exterior. Neoendothrix Trichophyton 



2. Suppurative reactions occur. Lesions of smooth skin also frequently present. 

 Some strains of animal origin. Fungus grows in and on the hair, spores 

 mostly external. 



a. Spores arranged in rows, not in mosaic. 



Edoihrix Trichophyton 

 aa. Spores in hair 5 to 8 microns in diameter. 



Section Megaspores 

 bb. Spores in hair 3 to 4 microns in diameter. 



Section Microides 



h. Spores in mosaic pattern. 



Microsporum Canis 



Lesions of the Smooth Skin 



A. Eczema-hke lesions confined to moist parts, as inner surfaces of thighs, axillary 

 regions, between fingers or toes, soles of feet. Not found within hairs. In 

 culture, greenish yellow, no conidia, macroconidia egg-shaped to clavate, thick, 



smooth walls. 



Epidermophyton {E. fioccosum) 



B. Lesions not as above, generally involving hands, arms, general body surface, 

 face, neck. 



1. Lesions form intricate patterns of concentric rings with marked scaling. 

 Hairs not invaded. • Trichophyton concentricum 



2. Lesions are reddish patches, not raised above the skin level, round to irregu- 

 lar in form, darker at the border, forming rings. Tending to heal in the 

 center, new attacks may occur, forming concentric rings. 



Generally Microsporum 

 Sometimes Endothrix Trichophyton 



3. Lesions are elevated plaques, reddish, round or oval, scaly. Pustules fre- 

 quently present at the border. Ectothrix Trichophyton 



