Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by rapidly progressive, painful ulcerations that often mimic infectious processes. Vulvar involvement is an uncommon presentation, particularly in pediatric patients, making the diagnosis especially challenging. We report the case of a nine-year-old girl who presented with rapidly evolving vulvar ulcerations that were unresponsive to intravenous and topical antibiotics. Because of the unusual clinical presentation and lack of response to antimicrobial treatment, a skin biopsy was performed, revealing dense neutrophilic dermatitis consistent with PG. An extensive evaluation failed to identify any associated systemic disease. After initiation of corticosteroid therapy, the patient showed marked clinical improvement, supporting the diagnosis of PG. This case describes an atypical pediatric presentation of vulvar PG and highlights the importance of considering PG in the differential diagnosis of persistent vulvar ulcerations. Early recognition may prevent unnecessary antimicrobial exposure, reduce diagnostic delays, and allow prompt initiation of appropriate immunosuppressive therapy.

Pyoderma gangrenosum (PG) is a rare dermatologic disease resulting in chronic, painful ulcerations, most commonly on the lower extremity. Pruritus is a common symptom in many dermatologic conditions but has not been thoroughly evaluated in patients with PG. We sought to characterize the prevalence, severity, and impact on QOL of lesional pruritus in patients with PG. Data were obtained from the "Pyoderma Gangrenosum Study" (IRB#16753) at Oregon Health and Science University. Standardized outcome data were prospectively collected during clinical encounters from December 2019 to May 2024. Inclusion criteria were adults who presented for at least 2 clinical visits and a PARACELSUS score ≥10. We analyzed data from 136 patients with 178 ulcers. At baseline, 69% of the patients reported moderate pruritus with a mean severity of 3.3 (0-10 scale, 95% confidence interval = 2.9-3.8), which decreased with healing (from 3.7 to 2.6). QOL scores (Skindex-Mini, Wound-QoL) improved in parallel with healing. Higher pruritus severity was associated with younger age and inflammatory arthritis, whereas analgesic use and systemic therapies showed no consistent associations. In summary, our findings suggest that lesional pruritus is a common symptom among patients with PG and significantly affects their QOL. These findings support routine assessment and antipruritic interventions in the management of PG.

Neutrophilic dermatoses, including pyoderma gangrenosum (PG) and Sweet syndrome (SS), are inflammatory disorders characterized by neutrophilic infiltration without infection. Conventional therapies are often inadequate. We aim to evaluate the efficacy and safety of JAK inhibitors (JAK-I) in the treatment of PG and SS. The study was registered (PROSPERO-CRD420251113331), and a relevant search was conducted on PubMed/MEDLINE, Scopus, Web of Science, and Embase until July 27, 2025. Included studies were English language reports describing PG or SS treated with any JAK-I or cases of JAK-I-associated SS. Reviews, animal studies, and reports with insufficient clinical data were excluded. Four reviewers independently screened records. Data extraction included demographics, comorbidities, treatment regimens, outcomes, and adverse events. Risk of bias was assessed using the National Heart, Lung, and Blood Institute and Murad et al. tools through discussion-based consensus. Due to heterogeneous outcome definitions and small sample sizes, only descriptive synthesis was performed. Fifty-four reports, including 70 patients (59 PG, 5 SS) treated with JAK-I and 6 JAK-I-associated SS, were included. Across 43 PG studies, five JAK-Is-tofacitinib, upadacitinib, baricitinib, abrocitinib, and ruxolitinib-produced 33 complete and 26 partial responses. Twenty-six patients (44.1%) received monotherapy. Most patients (51/59; 86.4%) had at least one comorbidity. Adverse events occurred in 6 (10.1%), including anemia, hypertension, renal dysfunction, fatigue, and acneiform eruption. Among 11 SS reports, all 5 treated patients achieved complete resolution with baricitinib, ruxolitinib, or filgotinib. Six additional cases described ruxolitinib-associated SS, generally improving with corticosteroids or drug withdrawal. Most studies were rated good quality. Evidence is limited to small cases with heterogeneous outcome definitions, variable dosing, and inconsistent follow-up. JAK-Is are associated with clinical improvement in PG and selected SS cases and may serve as useful adjunct therapies, though caution is needed in patients with hematologic malignancies. Larger controlled studies are needed.

The prognosis of melanoma has significantly improved since the introduction of immune checkpoint inhibitor (ICI) therapies. While ICIs are associated with a range of immune-related adverse events (irAEs), these reactions may occur early or late during treatment. Neutrophilic dermatoses, including pyoderma gangrenosum, are commonly observed in patients with systemic inflammatory disease, but have also been reported as rare cutaneous irAEs. To further characterize this rare phenomenon, we present the case of a 45-year-old patient with stage IIB cutaneous melanoma who underwent surgical resection of the primary tumor with split-thickness skin graft coverage, followed by adjuvant therapy with the PD-1 inhibitor nivolumab. During the one-year course of immunotherapy, the donor site of the graft exhibited persistent non-healing and progressive ulceration. However, it did not extend beyond the boundaries of the initial harvest site. Of note, the recipient site at the left heel healed without complications. The lesion was biopsied after completion of immunotherapy. Histopathological analysis revealed a neutrophilic dermatosis with PG-like features. The lesion showed rapid improvement upon initiation of dapsone therapy, which is in line with its action on neutrophils. This case underscores the diagnostic challenge posed by atypical cutaneous irAEs, particularly when localized and lacking systemic features. Awareness of such rare presentations is crucial to enable timely recognition and appropriate treatment.

Sweet syndrome (SS) is an autoinflammatory neutrophilic dermatosis characterized by abrupt-onset inflammatory skin lesions and systemic symptoms, yet its molecular pathogenesis remains incompletely defined. To delineate disease-specific inflammatory programmes, we performed NanoString-based transcriptomic analysis of SS skin lesions and compared them with healthy control skin and pyoderma gangrenosum, a related neutrophilic dermatosis. SS exhibited a distinct inflammatory transcriptional signature marked by robust upregulation of type I and II interferon-stimulated genes, including CXCL9, CXCL10, GBP1, GBP5, IFIT2 and IRF7, distinguishing SS from both control groups. Cell type deconvolution analysis revealed enrichment of dendritic cells, consistent with a prominent type I interferon-driven immune response. In parallel, SS lesions demonstrated altered immunoproteasome gene expression, with upregulation of immunoproteasome subunits PSMB8, PSMB9 and PSMB10 and downregulation of the constitutive subunit PSMB7 suggesting functional remodelling of proteasomal activity. Together, these findings support a model in which dendritic cell-driven interferon signalling promotes immunoproteasome remodelling and sustains neutrophilic inflammation in Sweet. This study identifies a prominent interferon signalling as a defining molecular feature of SS and highlights potential therapeutic opportunities within the interferon-JAK/STAT and proteasome pathways.

Pyoderma gangrenosum (PG) is a rare but challenging extraintestinal manifestation (EIM) of inflammatory bowel diseases (IBD), affecting 6%-48% of IBD patients. This retrospective study analyzed affected patients and evaluated therapeutic strategies for both IBD remission and PG resolution. A multicenter retrospective analysis was conducted on patients with IBD and PG in eight tertiary IBD centers. Demographic data, prior therapies, surgeries, and treatment of PG were collected retrospectively, and treatment responses were assessed. The cohort included 50 patients (median age: 43 years; 68% female). Crohn's disease was present in 58% and ulcerative colitis in 42%. Fifty percent of patients had prior surgery, 68% had an intestinal stoma in their medical history. 48% were experienced with biologic therapy, predominantly anti-tumor necrosis factor (TNF) therapy (83%). PG mainly affected the lower extremities (52%) and peristomal areas (24%). Systemic steroids were used in 52% (26/50) and led to PG resolution in only 11.5% (3/26). Anti-TNF therapy was the main approach, used in 68% (34/50) of patients, with resolution achieved in 80% (27/34). Calcineurin inhibitors were given to 26% (13/50) of patients and induced resolution in 38% (5/13). Three of six non-responders were successfully switched to infliximab. Overall, PG resolution was achieved in 80% (40/50), correlating with IBD remission in 78% (31/40) of these patients. The median time to PG resolution was 4 months. Anti-TNF therapy was an effective treatment for PG in IBD patients, even in those with prior nonresponse to calcineurin inhibitors. Systemic steroids showed low response rates. PG healing mostly aligned with IBD remission, underlining the need for tailored long-term therapy.

Pyoderma gangrenosum is a rare autoimmune condition that is difficult to diagnose and primarily affects the skin. Extracutaneous manifestations, including hepatic involvement, occur only rarely. Here, we report a case of extracutaneous manifestation of pyoderma gangrenosum without adjunct skin lesions, emphasizing the diagnostic challenges, immunological considerations, and therapeutic implications. This case describes a 73-year-old man presenting with isolated hepatic and ocular involvement of pyoderma gangrenosum, without skin lesions and without an underlying chronic inflammatory disease. This case aims to expand the clinical understanding of the spectrum of pyoderma gangrenosum, reinforce its systemic nature, and contribute to improved recognition of extracutaneous disease involvement even without primary skin manifestation. The patient exhibited fever, weight loss of 3 kg within 3 weeks, elevated hepatocellular and cholestatic liver parameters (AST: 128 U/L, upper limit norm [ULN]: 34 U/L; ALT: 116 U/L, ULN: 59 U/L), and elevated CRP (147.5 mg/L, ULN: 10 mg/L). Imaging revealed disseminated nodular liver lesions. Histology demonstrated sterile abscesses and granulomatous inflammation. Ophthalmologic examination revealed conjunctival injections and granulomatous uveitis. No other organs were involved. Extensive testing excluded infectious or other immunological causes. After comprehensive screening for infectious, rheumatological, malignant, or hematological diseases, systemic inflammatory syndromes, and drug-induced liver injury, none of the suspected common diagnoses could be confirmed. In relation to the distinctive histological pattern resembling a few published case reports, we assumed pyoderma gangrenosum with hepatic and ocular involvement without skin lesions. We initiated immunosuppressive treatment with prednisone, followed by infliximab. This strategy successfully led to symptom resolution and complete clinical and biochemical remission. This case highlights the diagnostic challenges of granulomatous liver injury and pyoderma gangrenosum at unusual sites. Pyoderma gangrenosum is a rare condition, particularly when presenting with isolated hepatic and ocular involvement, and may be considered a differential diagnosis underlying granulomatous hepatic injury. Using a TNF-alpha inhibitor, we successfully achieved a complete remission.

Pyoderma gangrenosum is a non-bacterial inflammatory disease that forms ulcers and abscesses and can be exacerbated by mechanical stimulation. Surgical intervention for abscesses in the corpora cavernosa may exacerbate penile pyoderma gangrenosum. We report a case of penile pyoderma gangrenosum that was diagnosed minimally invasively by biopsy alone and treated with steroids. A 77-year-old man with penile swelling and pain was referred to our institution by his primary care physician for suspected penile cancer. Both infectious diseases and penile cancer were ruled out based on physical examination and laboratory test results. Magnetic resonance imaging revealed fluid accumulation in the corpora cavernosa, leading to the decision to perform a penile biopsy. The biopsy revealed no malignancy, but an abscess was identified. Based on the clinical presentation, penile pyoderma gangrenosum was suspected and steroid therapy was initiated, resulting in rapid symptomatic improvement. The steroid dose was gradually tapered, and after 18 months of treatment, the steroids were discontinued. The patient has remained asymptomatic with no recurrence of the abscess or other subjective complaints.

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by rapidly progressive necrotizing skin ulcers. PG following cesarean section (CS) is extremely rare and frequently misdiagnosed as surgical site infection, leading to inappropriate debridement and disease exacerbation. We report a case of severe postcesarean PG successfully managed with early immunosuppressive therapy.

Extraintestinal manifestations (EIMs) are a significant disease burden in inflammatory bowel disease (IBD). However, large-scale epidemiological data from the Chinese population remain scarce. This nationwide, multicenter, retrospective cross-sectional study included 2,252 adult IBD inpatients from 10 clinical centers. Data on demographics, clinical features, and EIMs were collected and analyzed using descriptive statistics and logistic regression. Of the 2252 patients, 384 (17.1%) reported at least one EIM. Among these, data on temporal sequence were available for 310 patients, of whom 70 (22.6%) developed their first EIM before the onset of intestinal symptoms. The overall prevalence of EIMs was significantly higher in Crohn's disease (CD) than in ulcerative colitis (UC) (20.5% vs. 15.4%, P = 0.003). Joint manifestations (10.0%) and aphthous ulcers (5.5%) were most common, with aphthous ulcers significantly more frequent in CD (11.2% vs. 2.8%, P < 0.001). The prevalence of classic EIMs such as arthritis/arthralgia (8.0%), uveitis (0.5%), and erythema nodosum (0.9%) fell within the low-to-mid range of global reports. Significant co-occurrence was observed among EIMs. For example, arthritis/arthralgia showed strong associations with uveitis (OR = 31.88) and erythema nodosum (OR = 13.34). Analysis of medication history revealed higher use of infliximab in patients with arthritis/arthralgia (47.0%) and pyoderma gangrenosum (71.4%), and frequent glucocorticoid use in those with venous thromboembolism (72.4%). In this inpatient-based cohort, the lower prevalence of classic EIMs in Chinese IBD patients may reflect clinical underdetection or genuine epidemiological differences. EIMs can precede intestinal symptoms and influence each other, underscoring the need for proactive, systematic assessment in clinical practice.

Polypoid melanomas are unusual, as are amelanotic ones. Similarly, polypoid melanomas are not usually acral or amelanotic. They can be challenging to diagnose clinically, as they may resemble acral lentiginous nevus, polypoid Spitz nevus, eccrine poroma, schwannoma, pyogenic granuloma, verrucous carcinoma, fibrosarcoma, basal cell carcinoma, and pyoderma gangrenosum. We delineate a 64-year-old woman with an acral amelanotic polypoid melanoma on her sole. It was successfully removed surgically without limb amputation.