La myase ou hypodermose est une parasitose en voie de disparition. Nous en rapportons un cas survenu en Basse-Normandie.

Observation. - Caroline, sept ans, a été hospitalisée en novembre 1998 pour un oedème palpébral supérieur et inférieur droit, indolore, non inflammatoire, de volume variable dans le temps, responsable d'un ptosis, accompagné de nodules sous-cutanés sus-orbitaires droits, apparus dix jours auparavant. Les examens complémentaires comportant en particulier la recherche d'une hyperéosinophilie et les sérologies de l'hypodermose et de la toxocarose étaient normaux. Caroline a présenté plusieurs poussées oedémateuses, l'oedème devenant de plus en plus ecchymotique et douloureux. Après un mois et demi d'évolution, une hyperéosinophilie est apparue et la sérologie de l'hypodermose est devenue positive. Une corticothérapie brève (sept jours) par voie orale a été décidée, compte tenu de la gêne visuelle secondaire à l'importance de l'oedème palpébral. Par la suite, Caroline n'a pas eu de nouvelle poussée oedémateuse, et les nodules sous-cutanés ont disparu. La larve ne s'est pas extériorisée.

Conclusion. - Dans les régions d'élevage bovin, il faut savoir garder à l'esprit le diagnostic d'hypodermose devant des signes cliniques évoquant une migration larvaire, même en l'absence d'hyperéosinophilie et de positivité initiale de la sérologie. Cette affection devrait être éradiquée en raison de l'existence de programmes régionaux de traitement systématique du cheptel bovin.

Although myiasis or hypodermyiasis is a parasitic disease that theoretically has practically been eradicated, a new case has recently been reported in Lower Normandy, in a bovine husbandry region.

Case report. - A seven-year-old-girl was hospitalized in November 1998 for an edema of variable size on the right eyelid, which was not painful and non-inflammatory, with accompanying ptosis. A number of subcutaneous nodules were found on the forehead above the right eye socket. The right eye itself was unaffected. The symptoms had evolved over a ten-day period. Further examination did not detect any sign of eosinophilia, and the hypodermyiasis and toxocarosis serologies were negative. The clinical evolution was characterized by the regression and reappearance of the edema on several occasions, after which the edematous mass became progressively larger, more swollen and painful, so that it was no longer possible to open the eye. The subcutaneous nodules partially disappeared when the edema increased in size. Six weeks after the onset of clinical signs, eosinophilia was observed and the hypodermyiasis serology was positive. Due to the limitation of the visual field as a result of the edema, a short-term steroid treatment (seven days) was orally administered. The patient recovered, and no further edematous signs were noted. However, contrary to what had been reported in the literature, the larvae did not appear on the surface of the skin.

Conclusion. - In conclusion, in bovine husbandry regions the diagnosis of hypodermyiasis should always be kept in mind in the event of clinical signs indicative of larval migration, even in the initial absence of eosinophilia, and even with an initially negative hypodermyiasis serology. This disease should soon be eradicated, as regional bovine treatment programs have been set up to systematically treat the cattle and eliminate the larvae.