Arun Kumar A U, Elsayed Mohamed E, Alghali Ahmed, Ali Alaa A, Mohamed Husham, Hussein Wael, Hackett Catriona, Leonard Niamh, Stack Austin G
1Division of Nephrology, Department of Medicine, University Hospital Limerick, St Nessans Rd, Limerick, Ireland.
2Graduate Entry Medical School, University of Limerick, Limerick, Ireland.
Allergy Asthma Clin Immunol. 2018 Nov 8;14:46. doi: 10.1186/s13223-018-0265-6. eCollection 2018.
Sweet syndrome is a rare skin condition characterised by fever, neutrophilia, and tender erythematous skin lesions and has been reported to occur in association with anti-neutrophil cytoplasmic antibodies (ANCA) as well as complicate treatment with azathioprine therapy. Azathioprine, a relatively safe immunosuppressive, is frequently used to maintain disease remission in the treatment of ANCA-associated vasculitis. The occurrence of Sweet syndrome in a patient with ANCA-positive vasculitis and following treatment with azathioprine prompted us to present this clinical case and share this unusually rare occurrence. In doing so, we also wish to discuss current understanding of the disease and plausible associations.
Herein, we discuss the case of a 54-year old white male, who presented with features of ANCA vasculitis with haemoptysis, arthralgia, abnormal kidney function with active urine sediment and a positive p-ANCA titre. Standard immunosuppressive treatment with corticosteroids and intravenous rituximab resulted in disease remission. Due to significant steroid side effects, his steroid treatment was gradually tapered and switched to azathioprine over a 6-month period. Two weeks following initiation of azathioprine, he developed a painful maculo-papular erythematous skin rash and fever. A skin biopsy confirmed classical features consistent with Sweet syndrome. Withdrawal of azathioprine and treatment with oral corticosteroids and colchicine therapy resulted in complete resolution of the rash, although he continued to have high titres of MPO positive ANCA.
Sweet syndrome is a rare adverse reaction to azathioprine but has also been reported to occur in association with ANCA vasculitis. The temporal association with azathioprine in our case and the relatively rapid resolution of the skin vasculitis upon its withdrawal suggested a primarily drug-induced reaction rather than an associated feature of ANCA vasculitis.
Sweet综合征是一种罕见的皮肤疾病，其特征为发热、中性粒细胞增多以及压痛性红斑性皮肤损害，据报道可与抗中性粒细胞胞浆抗体（ANCA）相关，也可使硫唑嘌呤治疗变得复杂。硫唑嘌呤是一种相对安全的免疫抑制剂，常用于维持抗中性粒细胞胞浆抗体相关血管炎治疗中的疾病缓解。一名抗中性粒细胞胞浆抗体阳性血管炎患者在接受硫唑嘌呤治疗后发生Sweet综合征，促使我们呈现此临床病例并分享这一异常罕见的情况。在此过程中，我们还希望讨论对该疾病的当前认识以及可能的关联。
在此，我们讨论一名54岁白人男性的病例，他表现出抗中性粒细胞胞浆抗体血管炎的特征，伴有咯血、关节痛、肾功能异常且尿沉渣活跃以及抗蛋白酶3型抗中性粒细胞胞浆抗体（p-ANCA）滴度呈阳性。使用皮质类固醇和静脉注射利妥昔单抗进行标准免疫抑制治疗后疾病缓解。由于显著的类固醇副作用，他的类固醇治疗逐渐减量，并在6个月的时间内换用硫唑嘌呤。开始使用硫唑嘌呤两周后，他出现了疼痛性斑丘疹性红斑皮疹和发热。皮肤活检证实了与Sweet综合征一致的典型特征。停用硫唑嘌呤并采用口服皮质类固醇和秋水仙碱治疗后皮疹完全消退，尽管他的髓过氧化物酶（MPO）阳性抗中性粒细胞胞浆抗体滴度仍然很高。
Sweet综合征是硫唑嘌呤罕见的不良反应，但也有报道称其与抗中性粒细胞胞浆抗体血管炎相关。在我们的病例中，与硫唑嘌呤的时间关联以及停药后皮肤血管炎相对迅速的消退表明这主要是药物诱导的反应，而非抗中性粒细胞胞浆抗体血管炎的相关特征。
