[Borderline leprosy as a rare differential diagnosis].

History and clinical findings | A 42-year-old migrant from Brazil presented with persistent sensory disturbances, skin discolorations and local alopecia in the upper limbs. Decisive for the presentation in our Tropical Medicine Clinic were new occurrences of severe pain and redness and swelling in the area of the lesions that had already been assessed by a number of medical specialists without a clear diagnosis could be made. Investigations and diagnosis | The histological analysis of skin biopsies showed perivascular, perineural, periadnexial lymphocytic and granulomatous dermatitis. In a direct microbiological preparation individual acid fast bacilli could be detected (Ziehl-Neelsen stain). The electroneurographical examination demonstrated a sensitive peripheral-neurogenic damage with emphasis on the right median nerve and the left ulnar and radial nerves. Thermography revealed an increased heating or cooling threshold. The serological investigation by ELISA for IgM antibodies against the phenolic glycolipid (PGL-1) was positive (titer 1 : 1200). In summary, the diagnosis of borderline leprosy (infection with Mycobacterium leprae) with transition to multibacillary leprosy (according to WHO) and leprosy reaction type 1 was made. Treatment and course | We initiated an oral antimycobacterial therapy (multidrug therapy, MDT) with rifampin, clofazimine and dapsone for 12 months (WHO regimen for multibacillary leprosy). Leprosy reaction type 1 was treated with prednisolone and by increasing the dose of clofazimine. Analgesic therapy on demand was carried out with nonsteroidal anti-inflammatory drugs (ibuprofen). MDT and successful management of leprosy reaction lead to a rapid improvement of symptoms. Conclusions | Leprosy is an infectious disease occurring only rarely in Germany (average incidence of 1-2 cases per year) that is diagnosed almost exclusively among migrants. Main symptoms comprise non-itchy, reddish, touch insensitive skin lesions or nerve deficits. The diagnosis is based primarily on the clinical presentation, supplemented by pathogen detection, histology, neurophysiological findings and serology. Standard therapy is a combination of rifampin, clofazimine and dapsone (WHO scheme) for at least 6 months.