Contents

SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferences

View all Images (10)

Other Resources UpToDate PubMed

Loiasis

Contributors: Zachary Thomas, Edith Lederman MD, Cristina Thomas MD, Susan Burgin MD
Other Resources UpToDate PubMed

Synopsis

Loiasis is caused by the filarial parasite Loa loa. The disease is endemic to Central and West Africa. The infection is transmitted to humans by the bite of blood-sucking flies of the genus Chrysops (deer fly, horse fly, mangrove fly). The clinical picture of loiasis differs between those individuals residing in endemic areas compared to visitors to these areas.

In long-term residents of endemic areas, infection can be asymptomatic despite large numbers of microfilariae in the blood.

Because travelers to endemic regions are not immune to L loa, infection is characterized by localized subcutaneous swellings (Calabar swellings) and angioedema, both representing localized allergic reactions to L loa. These swellings are transient, lasting several hours to days, and most commonly occur on the extremities and face. Occasionally, migration of adult worms can be seen within or outside of the Calabar swellings as a moving wormlike structure. Pruritus or pricking sensations from adult worm migration is common in addition to arthralgia, fatigue, and myalgias. If the adult worm migrates under the conjunctiva (seen in 10%-20% of patients), a Calabar swelling can occur periorbitally, and this can be associated with eye pain.

Complications can include meningitis, encephalitis, nephropathy, endomyocardial fibrosis, and rarely, pulmonary involvement. Although loiasis is generally thought to be benign, these complications and an increased risk of mortality are more often seen in patients with high microfilariae levels and those living in endemic areas.

Codes

ICD10CM:
B74.3 – Loiasis

SNOMEDCT:
44250009 – Infection caused by Loa loa

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

To perform a comparison, select diagnoses from the classic differential

Subscription Required

Best Tests

Subscription Required

Management Pearls

Subscription Required

Therapy

Subscription Required

References

Subscription Required

Last Reviewed:03/22/2022
Last Updated:03/23/2022
Copyright © 2024 VisualDx®. All rights reserved.
Loiasis
A medical illustration showing key findings of Loiasis : Fatigue, Central Africa, Eye burning, Eyelid edema, West Africa, Arthralgia, Myalgia, Ocular pruritus, Paresthesias, Pruritus, EOS increased
Clinical image of Loiasis - imageId=229728. Click to open in gallery.  caption: 'Marked lymphedema of the left leg.'
Marked lymphedema of the left leg.
Copyright © 2024 VisualDx®. All rights reserved.