ONCHOCERCIASIS AND KELOID FORMATION 257 
forty, with extensive generalized keloidal tumors over the trunk and limbs, 
particularly over the chest and arms, and soft nodules in the lobes of the ears. 
The skin lesions were said to have commenced as pruriginous nodules at the age 
of thirteen years. 
The explanation for the marked tendency toward keloid growths among many 
African tribes is difficult. Sometimes an hereditary predisposition has been ob- 
served. Justus believes there is some relationship between hyperthyreosis and 
keloid formation, while Payr 2 believes that individuals with hypoplastic consti- 
tutions are especially predisposed to their formation, in fact to rich connective 
tissue formation in general, such as the production of adhesions. Menes,* how- 
ever, thinks that scrofula and syphilis predispose to keloids. None of these 
explanations except hereditary and racial tendencies seem to be particularly ap- 
plicable to the frequent occurrence of the condition among certain African 
peoples. Keloids frequently develop at the time of puberty or in the years 
immediately following. 
Ainhum. Ainhum was very prevalent in the interior of Liberia. It might 
be unilateral or bilateral and occasionally caused the loss of a fourth toe as well 
as of the fifth. Where the ring-shaped band of fibrous tissue had resulted in such 
loss the remainder of the foot was not pathologically altered. Stitt * points out 
that this condition is probably connected with a tendency to keloid development. 
The fact that ainhum often is said to be connected with injuries to the under sur- 
face of the toe would favor such a view. Often a fibrous cord has replaced the bony 
structures normally attaching the toe to the foot. Unna, who has investigated 
the pathological histology, found a ring-form scleroderma with thickening of the 
epidermis causing an endarteritis with the production of a rarefying osteitis. 
Such changes may be secondary to the primary proliferation of the fibrous tissue. 
Castellani ° who has observed similar changes to Unna, also points out that the 
constant irritation causes the epithelium to proliferate internally and depress 
the skin, and the fibrous connective tissue of the cutis to become increased in 
quantity. Zambaco ® believes that ainhum is a manifestation of leprosy. While 
we did not examine this lesion histologically in the cases of ainhum we observed 
in Liberia, there was certainly nothing to suggest leprosy in some of them, and no 
acid-fast bacilli were found in the cases examined. 
1 Justus: Arch. fiir Derm. und Syph. (1919), p. 127. 
2 Payr: Arch. fiir Klinische Chirurgie (1919), p. 116. 
3 Menes: Berl. klin. Woch. (1919), p. 11. 
4 Stitt: ‘Diagnosis and Treatment of Tropical Disease’’ (1929), Fifth Edition, p. 486. 
> Castellani: ‘‘Practice of Medicine in the Tropics” (1923), ed. by Byam and Archibald, III, 2438. 
6 Zambaco: Hansen u. Looft, Die Lepra, 1894, p. 1534. 
