XVIII 
ONCHOCERCIASIS AND KELOID FORMATION 
WHILE there is apparently no doubt that Onchocerca volvulus is the primary 
inciting factor in the formation of the neoplasms in the cases we have studied, 
one cannot lose sight of the fact that the tendency to the production of keloid 
growths among many Africans, subject to onchocercal tumors, is very common 
and marked, and that such growths may follow almost any form of injury or 
irritant applied to the skin. This fact is made use of by the natives in decorating 
the skin with various patterns by tattooing or scarifying the skin and sometimes 
inserting grains of indigo or camwood pigment (No. 47, page 71). Perhaps this 
tendency to abnormal reproduction of connective tissue following mechanical 
irritation sometimes may be an additional factor in the production of onchocer- 
eal fibromata which occasionally reach several inches in diameter. In Guate- 
mala I have never noticed any special tendency to keloid formation among the 
natives. The nodules produced by Onchocerca caecutiens as we have stated are 
usually situated about the scalp and generally vary in size from that of a pea up 
to an almond or walnut. In cattle infected with Onchocerca gibsoni, frequently 
examined in the Philippine Islands, the parasites usually le encysted in a fibrous 
capsule and the nodules are also not usually as large as a walnut. 
Keloid. The lesions of Case No. 384, a negress about thirty years of age, are 
illustrated in Nos. 192-1938. According to the statement obtained from her by 
one of us (through an interpreter), the lesions began about seven years ago on the 
arms, and were produced by magical medicine by a man who wished to kill her. 
According to the statement obtained by another of us, they followed burns with 
hot water. Such conflicting statements clearly demonstrate the fact that the 
medical histories obtained from native Africans are almost invariably worthless 
as far as authentic information is concerned. 
The lesions consist of large keloid-like nodular swellings on the sides of the 
neck, face, chest, breasts, shoulders, back, arms, legs, and flanks. They are ele- 
vated from 0.5 to 1.5 em. above the surrounding skin and the edges of some of 
them, particularly upon the back, bulge, and spread out slightly over the under- 
lying skin, so that they have a mushroom-like appearance. The diameter of the 
tumors varies from about 5 mm. to 15 mm. or more. Some of them have 
coalesced to form irregular masses. They are all sharply circumscribed but 
some are circular while others are irregular in outline. Retraction of the swell- 
ings in the bend of the elbow has produced a contracture so that the right arm 
is bent and fixed at an acute angle. The functions of both hands are impaired 
by searring and keloid formation on their backs. 
Some of the nodules show pitted scars and others more extensive sear for- 
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