Diagnosis: Onchocerciasis (river blindness, cutaneous form)
A 45-year-old male from West Africa presents with persistent pruritic skin lesions and subcutaneous nodules. The patient reports a history of significant exposure to fast-flowing rivers, leading to progressive skin changes and discomfort over several months.
A 45-year-old male from West Africa presents with a 6-month history of pruritic skin lesions and subcutaneous nodules. On examination, he exhibits multiple subcutaneous nodules over the trunk and extremities, with areas of lichenification and hyperpigmentation on the lower legs. The lesions are associated with intense itching and have resulted in significant discomfort.Subcutaneous nodules: Firm, movable nodules located primarily on the scalp, back, and extremities.Pruritus: Severe itching leading to excoriation and secondary changes.Lichenification: Thickened, leathery skin in areas of chronic scratching.Hyperpigmentation: Darkened patches of skin adjacent to the nodules.Regional lymphadenopathy: Mildly enlarged lymph nodes in the inguinal region.
The patient reports the onset of symptoms approximately 6 months ago, initially noticing small nodules on the scalp. He has a history of living near a river, which is a known risk factor for exposure to the vector. The pruritus has worsened over time, prompting him to seek medical attention. He has not received any prior treatments for these symptoms.Onset: Symptoms started 6 months ago with nodules appearing first on the scalp.Triggers: Exposure to fast-flowing rivers in endemic areas.Prior treatments: No previous treatments attempted for the skin lesions.Past medical history: No significant medical history; no known drug allergies.Family history: No family history of similar conditions.Social history: Resides in rural West Africa; occupations include farming and fishing.
Acute / First-Line ManagementIvermectin: Administer 150 µg/kg orally once, repeated every 6-12 months based on clinical response and local guidelines.Topical corticosteroids: High-potency corticosteroids may be used to manage inflammation and pruritus in localized lesions.Antihistamines: Oral antihistamines can be prescribed to alleviate itching.Workup and Diagnostic ConfirmationSkin snips: Obtain skin snips from nodules to identify microfilariae.Serology: Consider serologic testing for Onchocerca volvulus antibodies if available.Microscopy: Examine skin samples for the presence of adult worms or larvae.Long-Term ManagementRegular follow-up: Monitor for resolution of symptoms and any potential complications.Community health education: Promote awareness and preventive measures within the community.Additional treatments: Consider doxycycline (100 mg BID for 4-6 weeks) for patients with severe disease to target Wolbachia endosymbionts.
Leprosy: Characterized by hypopigmented skin lesions and peripheral neuropathy; history of exposure to endemic areas can assist in differentiation.Cutaneous larva migrans: Presents as an itchy, serpiginous rash; typically associated with a history of walking barefoot in sandy areas.Filariasis: May present with similar nodules; however, lymphatic involvement and acute filarial fever are distinguishing features.Psoriasis: Chronic skin condition with silvery scales; less likely given the patient’s demographic and exposure history.Scabies: Intense itching and rash can mimic symptoms, but burrows and a different distribution pattern are key features.Granuloma annulare: Presents with annular plaques; typically asymptomatic and more common in younger individuals.Mycosis fungoides: Consider in chronic skin lesions, especially with atypical features; requires biopsy for diagnosis.Cutaneous T-cell lymphoma: Rare but can present with pruritic skin lesions; histological evaluation needed for definitive diagnosis.
High-Yield PearlsGeographic risk: Onchocerciasis is endemic in certain regions, particularly near fast-flowing rivers in West Africa.Clinical features: Key symptoms include subcutaneous nodules, severe pruritus, and lichenification of the skin.Diagnosis: Confirmatory tests include skin snips and serology for Onchocerca volvulus.Treatment: Ivermectin is the first-line treatment; repeat dosing may be necessary based on local epidemiology.Long-term management: Regular follow-up is essential to monitor for complications and manage symptoms effectively.The presence of pruritic nodules in a patient from an endemic area should raise suspicion for onchocerciasis.
Tags: onchocerciasis, tropical