Dermatologica Sinica

: 2021  |  Volume : 39  |  Issue : 3  |  Page : 137--138

Histoid leprosy complicated with Charcot neuroarthropathy: A case report

Jen-Hao Hsu1, Yu-Hung Wu2, Pa-Fan Hsiao3,  
1 Department of Dermatology, MacKay Memorial Hospital, Taipei, Taiwan
2 Department of Dermatology, MacKay Memorial Hospital, Taipei; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan
3 Department of Dermatology, MacKay Memorial Hospital, Taipei; Department of Medicine, MacKay Medical College, New Taipei City; Department of Cosmetic Applications and Management, MacKay Medicine, Nursing and Management College, Taipei, Taiwan

Correspondence Address:
Dr. Pa-Fan Hsiao
Department of Dermatology, MacKay Memorial Hospital, Taipei

How to cite this article:
Hsu JH, Wu YH, Hsiao PF. Histoid leprosy complicated with Charcot neuroarthropathy: A case report.Dermatol Sin 2021;39:137-138

How to cite this URL:
Hsu JH, Wu YH, Hsiao PF. Histoid leprosy complicated with Charcot neuroarthropathy: A case report. Dermatol Sin [serial online] 2021 [cited 2021 Dec 5 ];39:137-138
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Full Text

Dear Editor,

A 65-year-old patient was diagnosed with leprosy about 50 years ago. He was treated with dapsone monotherapy for 2 years with remission from 1965 to 1967. A 3-month history of cutaneous manifestations was noted recently. On physical examination, several erythematous nodules and plaques were found on the right forearm, left elbow, and left upper arm [Figure 1]a and [Figure 1]b. Numbness of both hands, right drop foot, and sensory loss in the left forearm, right dorsal hand, and right leg were present. There were no palpable peripheral nerves. However, nerve conduction velocity examination showed asymmetric polyneuropathy involving the bilateral median, ulnar, peroneal, sural, and tibial nerves with axonal degeneration and demyelination.{Figure 1}

An incisional biopsy was performed on the lesion over the right forearm. There was diffuse histiocytic infiltration in the whole reticular dermis [Figure 1]c. The cells were negative for S-100 protein staining. Periodic acid-Schiff with diastase staining was negative for fungi. Acid-fast staining showed numerous positive bacilli [Figure 1]d. The pathological diagnosis was histoid leprosy.

A genetic drug resistance test was arranged and mutated folP-P55 L was detected, indicating resistance to dapsone. Therefore, a modified regimen of 100 mg oral clofazimine, 300 mg rifampin, and 100 mg minocycline per day instead of dapsone was prescribed. The treatment course was uneventful for 24 months. Slit-skin smear tests at 3-month intervals had been performed since antileprotic treatment began. The bacterial index decreased gradually. However, the results were persistently positive. After 24 months of treatment, the patient started to have erythematous to brownish swelling of the right foot. Computed tomography showed cellulitis and fasciitis along the right lower leg to foot associated with an abscess over the dorsal and medial aspect of the midfoot. The condition was coexistent with arthritis of intertarsal and tarsometatarsal joints, loose-body formation, and subluxation of the first intertarsal and Lisfranc joints [Figure 2]a, [Figure 2]b, [Figure 2]c. The report indicated acute infection with Charcot neuroarthropathy. We prescribed 400 mg moxifloxacin per day as infection control. The rifampicin dose was increased to 900 mg per day due to poor clinical control. The condition did not improve after altering the regimen 1 month later, and 750 mg oral levofloxacin per day was added as a second-line antileprotic treatment. The bony destruction was treated with orthosis and hyperbaric oxygen therapy. Unfortunately, the erythema on the right sole persisted and progressed to a nonhealing ulcer [Figure 2]d even after the acute infection was completely controlled. After discussing with the patient, we performed amputation to control the bony destruction. Levofloxacin had been administered for 6 months in total, and the follow-up slit-skin smears started to show negative for bacilli. The patient's condition is currently stable and slit-skin smears have remained negative for the past 2 years of follow-up.{Figure 2}

Histoid leprosy is multibacillary leprosy that is increasing in incidence.[1] Clinically, it manifests as cutaneous or subcutaneous asymptomatic papules or nodules. The lesions are commonly seen on the dorsal hands, arms, elbows, knees, thighs, buttocks, and lower back.[2] It is suggested that the treatment of histoid leprosy should be initiated as per the World Health Organization's multibacillary multidrug therapy, which is the combination of rifampin, clofazimine, and dapsone, but there is currently no consensus regarding the duration of therapy.[3]

Drug resistance in the treatment of leprosy is uncommon.[4] In the current literature, the resistance rate to dapsone is about 5.3%.[5] Insufficient therapy is the main cause of further drug resistance, especially for those who received dapsone monotherapy.[6] Multidrug therapy was not well-established decades ago and our case only received a 2-year regimen of monotherapy with dapsone 50 years ago, which may explain further drug resistance and recurrence.

Charcot neuroarthropathy is a progressive disease that deforms the bone and joints and is particularly apparent in the feet and ankles.[7] It is associated with certain neuropathies including diabetes, chronic alcoholism, syphilis, and leprosy.[7] Leprotic Charcot neuroarthropathy manifests as insidious, asymmetric, and mono- to poly-articular arthropathy.[8] The pathogenesis is not completely understood. Repetitive minor trauma to insensate joints, reactional states such as Type I and II lepra reaction, and infiltration of the nerves and synovium causing neurovascular compromise may be possible mechanisms. Management ranges from offloading, pharmacological therapy to surgical intervention such as exostectomy or arthrodesis. If the disease is intractable to these treatments or if the ulcer extends into the midfoot or hindfoot, amputation is usually necessary.[7] In our patient, although an instant and comprehensive therapeutic protocol including infection control, orthosis, and antileprotic medications were executed, the disease still progressed to a complicated condition and required amputation to prevent possible bony destruction due to chronic infection. The rare condition of neural and bony destruction complicated with leprosy was due to the incomplete course of the treatment for a prolonged duration. Modified treatment regimen was important in leading to a complete cure.

Ethical approval

This study was approved by the Institutional Review Board of MacKay Memorial Hospital (approval number: 20MMHIS432e; approval date: 2021.01.11). The patient consent was waived by the IRB.

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Conflicts of interest

Dr. Yu-Hung Wu & Dr. Pa-Fan Hsiao, editorial board members at Dermatologica Sinica, had no roles in the peer review process of or decision to publish this article. Dr. Jen-Hao Hsu declared no conflict of interest in writing this paper.


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