Dermatologica Sinica

: 2021  |  Volume : 39  |  Issue : 4  |  Page : 224--225

Successful treatment of metastatic Crohn disease with dapsone

Yu-Hao Chen1, Chao-Kuei Juan2, Chung-Hao Hsu3, Chung-Yang Yen2,  
1 Department of Medical Education, Taichung Veterans General Hospital; Department of Dermatology, Taichung Veterans General Hospital, Taichung, Taiwan
2 Department of Dermatology, Taichung Veterans General Hospital, Taichung; School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
3 Department of Dermatology, Taichung Veterans General Hospital, Taichung, Taiwan

Correspondence Address:
Dr. Chung-Yang Yen
Department of Dermatology, Taichung Veterans General Hospital, 1650, Sec. 4, Taiwan Bouleavard, Taichung

How to cite this article:
Chen YH, Juan CK, Hsu CH, Yen CY. Successful treatment of metastatic Crohn disease with dapsone.Dermatol Sin 2021;39:224-225

How to cite this URL:
Chen YH, Juan CK, Hsu CH, Yen CY. Successful treatment of metastatic Crohn disease with dapsone. Dermatol Sin [serial online] 2021 [cited 2022 Oct 7 ];39:224-225
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Full Text

Dear Editor,

A rare case of metastatic Crohn disease (MCD) is presented as follows. A 51-year-old man had a history of being a hepatitis B virus (HBV) carrier and of small-bowel resection due to multiple ulcerative lesions. In 2012, he was diagnosed with Crohn disease and was subsequently prescribed adalimumab from 2013 to 2018.

In August 2020, the patient experienced a flare of Crohn disease and was prescribed antibiotics, steroids, mesalazine, and azathioprine. The patient also exhibited extraintestinal manifestations of Crohn disease, such as arthritis and skin lesions, beginning in October; the rheumatologist suspected palindromic rheumatism. Several asymptomatic erythematous plaques emerged on his left thigh and bilateral lower legs [Figure 1]. A topical steroid was initially prescribed but was ineffective. A skin biopsy was performed on his left thigh and revealed mild perivascular lymphocytic infiltration in the dermis. Suppurative granulomatous inflammation was present at the interface between the dermis and subcutis, with focal involvement of an adjacent muscular vein [Figure 2]. The results of the Ziehl–Neelsen stain, periodic acid–Schiff (PAS) stain, and tuberculosis polymerase chain reaction (TB-PCR) all were negative. MCD was finally diagnosed. Despite the use of oral methylprednisolone (24 mg/day) and azathioprine (2 mg/kg/day), his skin lesions persisted. Given the patient's history as an HBV carrier, to reduce the risk of HBV reactivation, dapsone (100 mg/day) was prescribed instead of the dose of immunosuppressant being titrated. The patient's HBV viral load, total bilirubin, aspartate aminotransferase, and alanine transaminase were within the normal ranges in October 2020. After initiating the dapsone treatment, the patient's erythematous plaques completely subsided within 2 weeks; therefore, no sample was available for a mycobacterial culture. In addition, the patient's diarrhea and weight loss also improved. The patient had no record of adverse reactions after taking dapsone for 3 months. His weight increased from 51 to 53.5 kg within 3 months. In February 2021, adalimumab and anti-HBV drugs were prescribed by gastroenterologists to taper the patient's dose of methylprednisolone and azathioprine. Till July 2021, the patient has been using dapsone combined with adalimumab and azathioprine (0.5 mg/kg/day) for 6 months and has exhibited a positive response. He no longer experienced skin rashes and diarrhea appeared less frequently, and his body weight increased to 56 kg.{Figure 1}{Figure 2}

More than 40% of patients with Crohn disease experience skin and mucosal lesions as extraintestinal manifestations.[1] Crohn disease can be classified into the following three broad categories: Crohn disease can be classified into the following three broad categories: 1. Crohn disease characterized by peristomal and perianal cutaneous manifestations, 2. Crohn disease characterized by associated dermatoses, such as erythema nodosum, pyoderma gangrenosum, and neutrophilic dermatosis, 3. MCD, in which a patient's skin lesions are nonadjacent to the gastrointestinal tract.[2] MCD was first described in 1965 by Parks et al.,[3] and the term “metastatic Crohn disease” was coined by Mountain in 1970.[4]

MCD is sometimes difficult to distinguish from some infectious diseases, including syphilis, tuberculoid leprosy, sarcoidosis, TB, and fungal infections.[2] Therefore, diagnostics such as PAS stains, acid-fast bacilli tests, and TB-PCR are used in the differential diagnosis of MCD.

Histological findings in MCD include noncaseating granulomas in the superficial papillary and deep reticular dermis, which occasionally extend into subcutaneous fat. Other common features are the presence of multinucleated giant cells, perivascular lymphocytes, and abundant infiltration by monocytes and eosinophils. In addition, leukocytoclastic vasculitis, thrombogenic or granulomatous vasculopathy, and foci of extravascular neutrophilia are frequently observed in MCD.[5]

Till July 2021, no definite guidelines for treating MCD have been established. Based on the clinical experience described in a multiple case report, treatment options include topical or oral steroids, immunosuppressants, hyperbaric oxygen, and surgery.[6] Corticosteroids are considered the first-line treatment. Immunosuppressants can be used as second-line drugs. If the aforementioned treatments fail, the application of tumor necrosis factor alpha inhibitors is considered. The use of dapsone to treat refractory MCD has been previously reported.[7] Dapsone is often used in the treatment of neutrophil-mediated skin diseases and is known to have antimicrobial and immunomodulatory effects.[8] Some neutrophils were present in the perivascular infiltrate and the deep dermis in the pathology of our patient, which is a possible reason for the treatment success of dapsone. Although the patient was prescribed steroids, mesalazine, and azathioprine, his cutaneous lesions associated with MCD persisted until dapsone was administered. This case is of particular significance because it demonstrates the successful treatment of MCD with dapsone.

Declaration of patient consent

The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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