Patient selection: A person suspected of having onchocerciasis with negative results after a complete examination (skin snips, eye exam, etc.)
Dose: 25-50 mg diethylcarbamazine
A positive reaction is development of one or more of the following within a few hours of the dose:
(1) pruritis, which may be severe
(2) variable erythema
(3) ocular reaction (uveitis, other)
(4) systemic allergic response
The use of anti-inflammatory agents and antihistamines can reduce the severity of the reaction.
The reactions may be very severe in a patient with a heavy parasite load. It should not be done on someone with extensive disease if the infection can be diagnosed by another method.
A modification of test with less chance of a serious clinical reaction and therefore better patient acceptance is a patch test with the DEC applied topically. The site of application will develop a localized allergic reaction.
The test should not be done in a patient with allergy to diethylcarbamazine since this would cause a false positive reaction.
