A double-blind, placebo-controlled study of the efficacy of oral penicillin, diethylcarbamazine or local treatment of the affected limb in preventing acute adenolymphangitis in lymphoedema caused by brugian filariasis. 
Acute attacks of adenolymphangitis (ADL) contribute significantly to the morbidity seen in cases of filarial lymphoedema.  Such cases are now being treated with multiple courses of the antifilarial drug diethylcarbamazine (DEC), either alone or in combination with antibiotics or anti-inflammatory drugs, based on anecdotal experience.  In this, the first double-blind, placebo-controlled study, 150 patients with lymphoedema caused by brugian filariasis, each of whom recalled two or more ADL attacks in the previous year, were enrolled on a comprehensive foot-care programme.  Each was also randomly allocated to one of the following five daily regimens (30 patients/regimen) for 1 year: 800 mg oral penicillin; 1 mg DEC/kg; 800 mg oral penicillin plus 1 mg DEC/kg; local antibiotics; or placebo.  Each patient was followed up for another year.  For each regimen group (including the placebo group), the number of ADL attacks in the treatment year was significantly less than that in the year prior to treatment (P < 0.001).  Although, in all but the placebo group, there was a slight increase in the number of episodes in the follow-up year compared with the treatment year, the increase was only significant in the two groups given penicillin.  Of all the treatments tested therefore, foot care seems to play the most important role in the prevention of ADL attacks.  Additional benefit may accrue from local or systemic antibiotic use in those with high grades of oedema, but antifilarials have no place in the prevention of ADL attacks in an individual patient.  These observations should help in the rational management and prevention of ADL attacks in filarial lymphoedema, so that the progression of the disease may be halted and morbidity reduced.