Successful treatment of prurigo nodularis with abrocitinib: A case report

Dear Editor, A 40-year-old Taiwanese female with a history of childhood atopic dermatitis that spontaneously resolved in adulthood presented with a pruritic skin rash approximately 2 years after receiving the COVID-19 vaccination with the Moderna mRNA vaccine. Physical examinations revealed numerous itchy brownish nodules on all limbs, particularly on her bilateral arms, along with widespread symmetrical and itchy erythematous papules with lichenification [Figure 1a and b]. The pruritus significantly affected her sleep quality, as indicated by an 8-point score on the Visual Analog Scale (VAS) for pruritus. Laboratory tests revealed relative normality, with no eosinophilia or elevation in immunoglobulin E levels. No positive findings were observed for potential infectious risk factors, including hepatitis B virus, hepatitis C virus, or tuberculosis. The patient was diagnosed with prurigo nodularis (PN).Figure 1: Numerous nodules on the (a) right forearm and (b) left forearm before abrocitinib treatment. Following a 6-week course of abrocitinib treatment, significant relief of pruritus was observed, and the lesions demonstrated resolution, with residual erythema evident on the (c) right forearm and (d) left forearm.Initially, the patient received treatment with oral antihistamines and a high-potency topical corticosteroid agent. However, her pruritus persisted without significant improvement. After discussing options with the patient, oral abrocitinib was prescribed at a daily dosage of 200 mg, taking into consideration the side effects and the limited efficacy of conventional immune modulator agents. After 1 week of treatment, pruritus significantly decreased, with the VAS score of pruritus decreasing to 2 points. At the 6 weeks of treatment, the VAS score decreased to 0 points. The erythema and swelling of the nodules gradually faded [Figure 1 c and d]. The dosage was tapered gradually from a daily 200 mg to 100 mg and later 100 mg every other day. After 2 months of withdrawal, her pruritus recurred, necessitating the resumption of abrocitinib. Rapid remission was observed after 1 week without apparent adverse events. The patient continued the treatment with abrocitinib at a daily dose of 200 mg without tapering for 2 months. The exact pathogenesis of PN remains elusive. Nonetheless, prior studies have highlighted pronounced interplay and dysregulation between immune cells and neuronal circuitry, both playing pivotal roles in PN pathogenesis.[1] Immune dysregulation involves elevated T lymphocytes, mast cells, and eosinophilic granulocytes densely infiltrating the dermis in PN lesions, triggering inflammation, and itching by releasing various mediators, including interleukin (IL)-31, tryptase, eosinophil cationic protein, histamine, prostaglandins, and neuropeptides. T-cells and their cytokines, notably IL-31 and subsets of Th2 cytokines such as IL-4, also contribute significantly to PN pathogenesis. The binding of IL-31 to its respective receptors primarily activates JAK1, JAK2, and STAT3.[2] One case report documented a 63-year-old male diagnosed with PN after receiving COVID-19 vaccination was presumed to have a dysregulated immune response according to the hypothesis.[3] Concerning neural dysregulation, earlier studies have indicated a substantial increase in nerve fiber density within the dermis but notably fewer fibers in the epidermis of PN lesions, potentially implicating repeated mechanical scratching in this phenomenon.[1] Hence, the primary objective in managing PN is to disrupt the itch–scratch cycle, which typically involves traditional therapies such as topical treatments, phototherapy, and systemic therapies. Recently, many case reports and ongoing clinical trials have been exploring novel PN drugs. Although the exact mechanism of JAK inhibitors in PN treatment has not been fully elucidated, multiple studies have demonstrated their efficacy without any adverse effects [Supplementary Table 1]. Yin et al. reported successful treatment of refractory PN with baricitinib in a 37-year-old man, noting significant improvement and remission at a 4-month follow-up.[4] Liu et al. reported rapid remission and complete resolution of itch in nine patients with PN treated with tofacitinib.[5] Peng et al. also noted effectiveness during the 6-week administration of tofacitinib in a 65-year-old male with PN.[6] Muntaner Virgili et al. reported a positive response to upadacitinib treatment in a 53-year-old man after 16 weeks.[7] Vander Does and Yosipovitch reported successful treatment with abrocitinib in a 62-year-old female who showed poor treatment response to dupilumab.[8]In this patient, who developed a dysregulated immune response after vaccination, we prescribed oral abrocitinib, a small molecule that selectively targets the JAK1 protein, for PN. The patient experienced rapid remission within 1 week. However, itchy symptoms recurred after withdrawal for 2 months and previous studies did not provide recommendations regarding the overall treatment time. Besides, there is ongoing debate about whether JAK inhibitors elevate the risk for venous thromboembolism and herpes zoster, underscoring the need for long-term follow-up for further clarification. In conclusion, we present a case of PN successfully treated with abrocitinib. JAK inhibitors have emerged as promising treatment options for PN and have demonstrated efficacy without significant adverse effects. Further research is imperative to uncover the mechanisms of JAK inhibitors, assess potential side effects, and determine the recurrence rate in PN treatment. Ethical approval This study was conducted in accordance with the Declaration of Helsinki and was approved by the Institutional Review Board of Tri-Service General Hospital (TSGHIRB No.: C202415015), approved date: 2024/01/14. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent form. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed. Data availability statement The datasets generated during and/or analyzed during the current study are publicly available. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.sx