Leprosy detection rate in patients under immunosuppression for the treatment of dermatological, rheumatological, and gastroenterological diseases: a systematic review of the literature and meta-analysis

Background

Recently developed immunosuppressive drugs, especially TNF antagonists, may enhance the risk of granulomatous infections, including leprosy. We aimed to evaluate the leprosy detection rate in patients under immunosuppression due to rheumatological, dermatological and gastroenterological diseases.

Methods

We performed a systematic review of the literature by searching the PubMed, EMBASE, LILACS, Web of Science and Scielo databases through 2018. No date or language restrictions were applied. We included all articles that reported the occurrence of leprosy in patients under medication-induced immunosuppression.

Results

The search strategy resulted in 15,103 articles; finally, 20 articles were included, with 4 reporting longitudinal designs. The detection rate of leprosy ranged from 0.13 to 116.18 per 100,000 patients/year in the USA and Brazil, respectively. In the meta-analysis, the detection rate of cases of leprosy per 100,000 immunosuppressed patients with rheumatic diseases was 84 (detection rate = 0.00084; 95% CI = 0.0000–0.00266; I² = 0%, p = 0.55).

Conclusion

Our analysis showed that leprosy was relatively frequently detected in medication-induced immunosuppressed patients suffering from rheumatological diseases, and further studies are needed. The lack of an active search for leprosy in the included articles precluded more precise conclusions.

Trial registration

This review is registered in PROSPERO with the registry number CRD42018116275.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06041-7.

Lepromatous leprosy mimicking systemic lupus erithematosus: a case report

The clinical manifestations of leprosy are highly variable, and the disease is notorious for being “a great imitator” of several other conditions. Leprosy may manifest with a variety of phenomena resembling those of autoimmune diseases. Herein, we report a 33-year-old male presenting with wounds on his left leg and hyperpigmented skin lesions all over his body. Six years earlier, the patient was diagnosed with systemic lupus erythematosus (SLE). However, therapy for SLE did not control his symptoms; instead, the patient developed features of leprosy, such as anesthetic skin lesions, nerve enlargement, and tenderness. Tests for antinuclear antibodies and anti-double stranded DNA antibodies were negative. Slit-skin smear showed a bacterial index of 6+ and morphological index of 10 %. Lupus band test results were negative. Histological findings were compatible with lepromatous leprosy. The clinical and serological similarities between leprosy and SLE may lead to erroneous diagnosis. Thus, clinicians should be aware of this characteristic for correct diagnosis.

Leprosy: A great imitator

In recent years, advances in medical diagnosis and treatment have greatly attracted our attention, whereas some rare diseases, such as leprosy, have not found a place in the medical education curriculum; their existence may even be forgotten. Although the prevalence and incidence rates for leprosy have been significantly reduced as a result of the control strategies of the World Health Organization, new cases still appear. A total of 214,783 new cases were reported from 143 countries during 2016, corresponding to the global new-case detection rate of 2.9 per 100,000 population. Leprosy proves to be a very interesting model due to its immunologic properties. It joins with syphilis, mycosis fungoides, cutaneous tuberculosis, and sarcoidosis as one of the great imitators. The diagnosis of leprosy can be simple and practical, but considering the diagnosis of leprosy in the differential diagnosis is the first requisite again.