492 DISEASES OF THE SKIN 



(7) T. decalvans. 



An anomalous form of mirrosporosis of tlie scalp or bald ring- 

 worm. The hair falls out, leaving a bare patch in a place 

 previously unaffected or on an ordinary ringworm area. The 

 scalp is affected and the lesion resembles alopecia areata. 



(8) T. flava. 



Parasite, Malassezia tropica (Castellani, 1905). 



It is very common in all tropical countries. 



The mycelial threads are thick with numerous swellings and 

 constrictions. The spores are rounded or oval and have a 

 double contour, and often run into clusters. In chronic cases 

 the fungus is not so readily found. It is common amongst 

 the Russian poor. 



Attacks face, neck, chest and abdomen. 



Lesions begin as tiny spots, slowly enlarging, the tint varying 

 from deep orange yellow to deep canary yellow. There is no 

 itching or descjuamation. It tends to be very chronic. 



These " beauty " spots are liighly appreciated by some natives. 



Treatment. — Patience and perseverance are necessary for 

 months. 



A cold climate hastens the process of cure. 



Apply turpentine daily. For exposed parts use : — 



^ Resorcin i drachm 



Salicylic acid 10 grains 



For covered parts use : — 



Chrysarobin 20 per cent., or tincture of iodine. 



(9) T. imbricata. 



A form of body ringworm formerly peculiar to the East, but 

 now rapidly spreading in damp equable climates of 70° F. 

 to 90° F. 



It is produced by a trichophyton, and characterized by a 

 concentric arrangement of closely set rings of scaling 

 epidermis (Manson). It is not known in Africa. 



Parasite, Endodermophyton concentricum and E. indicum 

 (Castellani). 



Incubation, nine da}s. 



Attacks the whole body, but avoids hairy parts, especially the 

 scalp. The nails may be affected. 



Lesions commence as spots and develop into concentric rings 

 of tissue-paper-like scales about i inch a)5art and having one 

 free edge. Itching is generallv intense, but the general 

 health is unaffected. The condition tends to become chronic 

 without spontaneous recoyer\-. Relapses are common. 



