CALABAR SWELLINGS 



1973 



The way in which the worm induces these pecuHar lumps is a 

 matter of conjecture, Argyll Robertson assigning them merely to 

 the movements of the parasite. But this cannot be so, otherwise 

 the swellings would occur as they cross the bridge of the nose, 

 which they can do without any such disturbance. 



The next theory is that the parasite irritates the skin, causing 

 the patient to rub the affected area, which in this way becomes 

 mechanically inflamed. This theory was originally propounded 

 by Manson, who has relinquished it in favour of another and better 

 explanation. 



Two other theories suggest that the parasite, by irritating the 

 nerve endings, either directly or by reflex action, causes the swell- 

 ing; but this does not appear likely, as they ought to occur wherever 

 the worm travels. Manson in 1903 suggested that they might 

 be brought about by the expulsion of the microfilarise from the 

 uterusof the parent worm, and this appears not unlikely, and would 

 explain their evanescent character. 



Ward is not satisfied with Hanson's theory, and suggests that 

 they may be due to the expulsion of waste products from the worm. 



Age, sex, and employment have no influenee in the causation of 

 the complaint. 



Symptomatology. — Sometimes without prodromal symptoms, or 

 at times after some nausea and headache, swellings appear on the 

 head, face, arms, wrists, hands, fingers, ankles, or toes, lesscommonly 

 on other parts of the body. The reason of this distribution, accord- 

 ing to some authors, is believed to be the small amount of connective 

 tissue in those regions. The swellings are smooth, firm, slightly 

 elevated areas, generally about the size of half a goose's egg (5 to 

 8 centimetres), often painless, though this is not invariable. There 

 is either absence of or only very slight pruritus. They are ]iot, 

 and do not pit much on pressure. They appear quickly, last for 

 two or three days, and disappear gradually or rapidly, and are 

 always associated with an intense eosinophilia. In many cases 

 only one swelling appears at a time. 



Stephens gives the differential count of his case as — Polymorphonuclears, 

 26 per cent.; lymphocytes, 23 per cent.; mononuclears, i per cent.; eosino- 

 philes, 50 per cent. 



Diagnosis. — There is no difficulty in recognizing these fugitive 

 swellings in persons who have resided in the endemic region. The 

 presence of extremely well-marked eosinophilia may help in the 

 diagnosis. 



Prognosis. — They have never been known to cause serious symp- 

 toms, but may recur for many years after the patient has left the 

 tropics. 



Treatment. — This is unsatisfactory, but cool applications such as 

 diluted liquor plumbi (5 per cent.) may be made to the swelhngs, 

 and an ichthyol ointment or lotion applied. 



Prophylaxis.— As our knowledge of the life-cycle of Loa loa is very 

 incomplete, it is not possible to lay down rules for the prophylaxis. 



