Leprosy is an endemic mycobacterial infection caused by acid-fast bacilli (M. leprae) mainly involving the skin and the peripheral nerves 1, 2. The means of transmission is not fully understood 3; individuals with sufficient exposure and susceptibility to M. leprae complex may develop a broad range of clinical manifestations, which vary depending upon the host's ability to mount an acquired immune response to infection 3, 4. The spectra of immunological mechanisms can mimick connective tissue disorders 5.
Here we report a case of 31-year-old man, traveling from Ghana to Italy in 2016; the initial clinical findings (bullous erysipelas of the hands and hypotrophy of the hypotenar region with the flexion of the fourth and fifth proximal interphalangeal joints) suggested possible leprosy, but the skin biopsies were negative for mycobacteria. Over the following six years, the biochemical and hystopathological data together with the symptoms developed by the patient, have been evaluated separately by the various specialists (dermatologists, rheumatologists and nephrologists), with final diagnosis of lupus. Therefore, clinicians started immunosuppressive treatment, without improvement.
The absence of acid-fast bacilli in the skin biopsies and the lack of neurological manifestations delayed the diagnosis until the general conditions worsened (increase of proteinuria, generalized oedema, recurrence of skin ulcers, appearance of annular lesions); the patient was transferred to Referral Hospital to be tested for polymerase chain reaction (PCR).
The clinical, serological and histological similarities between leprosy and autoimmune diseases may lead to erroneous and delayed diagnosis, with potential clinical and emotional sequelae requiring long-life care.