Overview
Loa loa infection, caused by the filarial parasite Loa loa, is endemic in West and Central Africa and manifests primarily as migratory angioedema known as Calabar swellings. Expatriates with recent travel to endemic regions may present with characteristic skin manifestations despite varying exposure durations and atypical laboratory findings like normal eosinophil counts 1.Diagnosis
Clinical Presentation: Migratory angioedema (Calabar swellings) 1
Skin Biopsy: May reveal leukocytoclastic vasculitis 1
Laboratory Tests: Eosinophil count can be normal; consider in context of clinical presentation 1
Serological Testing: Not explicitly detailed in provided abstracts; typically used for confirmation 1
Imaging: Not typically required for diagnosis but may be used to rule out other conditions 1
Travel History: Essential for suspecting Loa loa infection 1
Parasitological Confirmation: Microfilariae detection in blood smear (most definitive) 1Management
First-Line Treatment: Diethylcarbamazine (DEC) is the mainstay; typical dose 30 mg/kg over 1-2 weeks 1
Adjunctive Therapy: Corticosteroids may be used to manage severe allergic reactions or angioedema 1
Monitoring: Close observation for adverse reactions, particularly during DEC therapy 1
Supportive Care: Symptomatic treatment for angioedema and associated symptoms 1
Duration: Treatment duration varies; typically guided by clinical response 1
Follow-Up: Regular monitoring for recurrence and complications 1Special Populations
Pregnancy: Specific management guidelines not detailed in provided abstracts; DEC use requires caution 1
Pediatrics: Dose adjustments may be necessary based on weight; close monitoring advised 1
Elderly: Increased vigilance for adverse drug reactions; individualized treatment plans recommended 1
Comorbidities: Management should consider potential interactions and exacerbation risks; expert consultation advised 1Key Recommendations
Consider Loa loa infection in differential diagnosis for patients with migratory angioedema, especially with travel history to endemic regions (Evidence: Moderate) 1
Perform blood smear for microfilariae detection for definitive diagnosis (Evidence: Moderate) 1
Initiate treatment with diethylcarbamazine (DEC) at 30 mg/kg over 1-2 weeks for confirmed cases (Evidence: Expert opinion) 1References
1 Rakita RM, White AC, Kielhofner MA. Loa loa infection as a cause of migratory angioedema: report of three cases from the Texas Medical Center. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 1993. link