CHAPTER XXXVII. 

 FAVUS. 



ACHORION SCHONLEINII (REMAK). 



FAVUS, or tinea favosa, is a chronic and destructive form of 

 dermatomycosis occurring in man and animals, caused by a 

 fungus discovered in 1839 by Schonlein,* and called in his 

 honor Achorion schonleinii by Remak in 1845. This fungus 

 is widely distributed and affects mice, cats, dogs, rabbits, 

 fowls, and men. Among human beings it usually occurs upon 

 the scalp and other hairy parts of the body, though it may 

 also affect the hairless portions and even attack the roots of 

 the nails. It is more frequent in children than in adults. 

 The fungus grows vigorously and usually forms a small 

 sulphur yellow disk about the base of a hair. The edges of 

 this detach, become everted, and the whole eventually sepa- 

 rates, forming the "scutulum," or characteristic lesion of the 

 disease. The reaction is more marked, the damage done 

 greater, and the disease less tractable than in other forms of 

 dermatomycosis . 



The infection seems to take place in most cases by way of 

 the hair-follicles, and the mycelia of the fungi grow into and 

 about the hairs, invading the epiderm, and causing atrophy 

 of the hair-follicles by pressure. Beneath and around the 

 scutulum, which consists chiefly of the fungi, an inflamma- 

 tory reaction takes place, and leukocytic invasion and ulcer- 

 ation cause the scutulum to separate. 



Although usually confined to the skin , the favus infection 

 may extend to the mucous membranes, and Kaposi and 

 Kundratf have reported a case in which favus fungi were 

 found to have invaded the stomach and intestines. 



The disease runs a course sometimes extending over many 

 years. Crocker J mentions a case that recovered after thirteen 

 years. It may remain localized upon the scalp or may spread 



* Muller's "Archiv.," 1839. 

 f "Ann. de Dermat. et de Syph.," 1895, p. 104. 

 J "Diseases of the Skin," Phila., 1903, p. 1276. 

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