TINEA CAPITIS TROPIC A LIS 



2057 



3. A. gypseum Bodin, 1907; very rare. 



The description of all these fungi is found in Chapter XXXVIII., 

 p. 988. 



Symptomatology. — It may be said in a general way that the 

 principal clinical signs are the same in the tropical types of the 

 affection as in the temperate zones, though the medical man who 

 has studied the subject thoroughly will soon be able to detect small 

 clinical differences, and will soon realize that as a general rule 

 each species of fungus gives rise to a slightly different type of 

 disease. 



Tinea Capitisr Microsporica (Microsporosis) . — Tinea capitis due to fungi of 

 the genus microsporum, usually known by the term microsporons in derma- 

 tological literature, is rare in tropical and subtropical countries. The affection 

 attacks, usually, only children. The affected patches are studded with stumps 

 of broken hair, which are loosened and brittle, have lost their natural gloss, and 

 show a whitened appearance caused by the fungus producing a greyish sheath 

 round the hair. The microscopical examination of the affected hair after 

 treatment with liquor potassse will show presence of so-called spores, roundish 

 or ovoid, 2-4 jll in diameter, irregularly distributed, while those of the tricho- 

 phytons are often larger (3-8 /j,), square with rounded angles, or somewhat 

 oblong, and arranged in definite regular chains. 



Tinea Capitis Trichophytica {Trichophytosis). — This is common in the 

 tropics and may be caused by a number of trichophytons which have been 

 mentioned in the ^Etiology. In Chapter XXVIII., p. 995, we have given a 

 botanical classification of the genus Trichophyton, creating several subgenera. 

 In most dermatological works, however, a simpler classification is followed. 

 Two groups are differentiated: endothrix and endo-ectothrix, the latter cor- 

 responding to the original Sabouraud's ectothrix. The endo-ectothrix 

 group is subdivided into two types: with large spores (megaspores), with 

 small spores (microides). Those of the microides type produce a greyish 

 sheath round the hairs, like the microsporons, but the so-called spores are 

 arranged in regular chains, a feature never observed in the microsporons. 

 The microides trichophytons are pyogenic, and often cause kerion. 



As we have already stated, each species of trichophyton gives rise to a 

 slightly different clinical type of the affection. Among the many types we 

 may briefly notice " Black-dot tinea tonsurans " and " Tinea decalvans 

 tropicalis." 



Black-dot Tinea Tonsurans.- — -This type is common in Europe, but is at times 

 observed also in subtropical and tropical countries. It is caused by Tricho- 

 phyton sahouraudi Blanchard, usually known in dermatological literature 

 by the name of Trichophyton acuminatum. The scalp presents scurvy patches 

 with minute dark dots, best seen with a lens. These dots are pigmented, 

 coiled up stumps. 



Tinea Decalvans Tropicalis. — This variety, described by Castellani, is common 

 in Ceylon. It generally attacks children, especially of the moormen com- 

 munity. The scalp presents one or several white patches covered with an 

 enormous number of heaped-up white pityriasic scales. The scales and the 

 broken hairs, examined microscopically, show presence of an endo-ectothrix 

 fungus, which, when cultivated, shows some characters of T. violaceum 

 Bodin [T . violaceum Bodin var. decalvans CasteUani). A very serious symptom 

 is that the patches as a rule remain permanently bald. 



Tinea Capitis Favica (Favus). — This affection, common in Southern and 

 Eastern Europe, is found in some subtropical countries, such as certain parts 

 of North Africa and China, but is rare in the tropics. The condition is recog- 

 nized by the sulphur-coloured cup-shaped scabs, the peculiar mousy odour 

 and presence of atrophic scarring. The hair is lustreless and discoloured, 

 but does not break off as in ringworm. 



