Superficial granulomatous pyoderma: a localized vegetative form of pyoderma gangrenosum

Pyoderma Gangrenosum: Diagnostic Criteria, Subtypes, Systemic Associations, and Workup

Pyoderma gangrenosum (PG) is an inflammatory neutrophilic dermatosis with variable clinical features. The classic presentation is an ulceration with an erythematous to violaceous undermined border. Extracutaneous manifestations may occur. Associated systemic diseases include inflammatory bowel disease, inflammatory arthritides, and hematologic disorders. The pathophysiologic mechanism of disease is not completely known but likely related to the cumulative impact of inflammation, immune-mediated neutrophilic dysfunction, and genetic predisposition. Incidence is between 3 and 10 people per million but may be greater due to under recognition. In this article, we will discuss the diagnostic criteria, disease subtypes, systemic associations, and workup.

Postoperative and Peristomal Pyoderma Gangrenosum: Subtypes of Pyoderma Gangrenosum

Postoperative pyoderma gangrenosum and peristomal pyoderma gangrenosum are 2 subtypes of pyoderma gangrenosum. The diagnosis is made as a clinicopathologic correlation when assessing a rapidly progressing ulcer with irregular and undermined borders following a surgical procedure, trauma, or the creation of a stoma. Familiarity with the associated risk factors and distinguishing features of these disorders can facilitate prompt recognition, proper diagnosis, and the initiation of treatment. Management usually involves the use of corticosteroids and steroid-sparing agents as immunomodulators to shift the inflammatory neutrophilic dermatoses to chronic noninflammatory wounds and eventual healing.

Clinical guidance of pyoderma gangrenosum 2022

Pyoderma gangrenosum (PG) is a rare, neutrophilic skin disease. For the purpose of accurate diagnosis and proper treatment of PG, the Japanese clinical practice guidance for PG developed by the Japanese Dermatological Association was published in 2022. In this guidance, clinical aspects, pathogenesis, current therapies, and clinical questions on PG are described from the viewpoints of current knowledge and evidence-based medicine. Here, the English version of the Japanese clinical practice guidelines for PG is presented and is intended to be widely referred to in the clinical examination and treatment of PG.

Annular neutrophilic dermatoses

Neutrophilic dermatoses (NDs) constitute a group of diseases characterized by sterile neutrophilic infiltrations. Many NDs usually present with infiltrated erythematous plaques, nodules, urticarial plaques, or pustules. Lesions may show variability, and atypical presentations may develop among NDs. Annular lesions have been reported in many NDs and may lead to diagnostic problems. Clinical features and histopathologic findings such as localization of the neutrophilic infiltrate, existence of other cell types, and absence of true vasculitis may be helpful to distinguish NDs. Some of these NDs are associated with infections, inflammatory diseases, and malignancies. In most NDs, systemic steroids and dapsone are very effective and usually first choices. Colchicine, antimicrobials such as doxycycline, tetracycline, and sulfapyridine, and other immunosuppressants such as cyclosporin, methotrexate, and mycophenolate mofetil have been used successfully in treating many NDs. Tumor necrosis factor α inhibitors have also been used successfully in treating many NDs. Janus kinase inhibitors are effective in CANDLE (chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature) syndrome, anakinra in neutrophilic urticarial dermatosis, and intravenous immunoglobulin in resistant pyoderma gangrenosum. We discuss the diagnosis and management of NDs that may present with annular lesions.

Pyoderma gangraenosum als diagnostische und therapeutische interdisziplinäre Herausforderung

Das Pyoderma gangraenosum (PG) ist eine neutrophile Dermatose unklarer Genese, die sowohl in Assoziation zu hämatologischen und neoplastischen Systemerkrankungen, chronisch-entzündlichen Darmerkrankungen und autoinflammatorischen Syndromen als auch idiopathisch auftreten kann. Sowohl die Diagnosestellung wie auch die Therapie des PG stellen aufgrund seiner Seltenheit, des Fehlens großer randomisierter kontrollierter Studien und der unzureichend verstandenen Pathogenese eine Herausforderung in der klinischen Praxis dar. Diese Übersichtsarbeit beschreibt und diskutiert aktuelle Erkenntnisse, die das PG als autoinflammatorische Erkrankung beschreiben. Durch eine Dysregulation von T-Lymphozyten und myeloiden Zellen wie den neutrophilen Granulozyten kommt es zur Entstehung von Pusteln und großflächigen Ulzera. Klassische Therapieansätze umfassen eine anti-inflammatorische topische Therapie, eine Analgesie sowie die systemische Gabe von Immunmodulantien oder -suppressiva. Neuere, bisher nicht zugelassene Therapieoptionen sind der Einsatz von Biologika und JAK-Inhibitoren.

Neutrophilic Dermatoses: a Clinical Update

Purpose of Review

Neutrophilic dermatoses are defined by the presence of a sterile neutrophilic infiltrate on histopathology. This review focuses on the pathogenesis, epidemiology, clinicopathological features, diagnosis, and management of four disorders: Sweet syndrome, pyoderma gangrenosum, Behçet syndrome, and neutrophilic eccrine hidradenitis.

Recent Findings

Recent studies have provided insight into the complex pathogenesis of neutrophilic dermatoses. Evidence supports an intricate interplay of abnormal neutrophil function and inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic predisposition.

Summary

Neutrophilic dermatoses have diverse cutaneous and extracutaneous manifestations and may be associated with significant morbidity and mortality. Common underlying associations include infectious, inflammatory, and neoplastic disorders, as well as drug reactions. Emerging diagnostic and therapeutic frameworks identify an expanding role for biologic and targeted anti-inflammatory therapies.

A Case Report of Necrotizing Eosinophilic Folliculitis Occurring After Rhus Ingestion

Necrotizing eosinophilic folliculitis is known as a rare variant of eosinophilic folliculitis (EF). It differs from classic EF because of its necrotizing ulcerative clinical course. We report a case of necrotizing eosinophilic folliculitis accompanied by pathergic phenomenon that may be the result of a delayed type hypersensitivity reaction occurring after Rhus consumption. Painful pyodermic plaques developed in a 48-year-old man, over a 5-day period, which was associated with facial edema. The lesions appeared 2 days after ingestion of Rhus. His face showed multiple painful pruritic papules that coalesced into crusted plaque accompanied by hemorrhagic eschars. At the periphery of the plaques, multiple erythematous papules and pustules were noticed. Prominent tissue eosinophilia was noticed from the skin biopsy samples. Also, there were areas of follicular mucinosis and eosinophilic folliculitis as well as hemorrhagic scale crust over the surface. Based on the clinical and histologic findings, the patient was diagnosed as necrotizing eosinophilic folliculitis occurring after Rhus ingestion. The lesions rapidly cleared after starting treatment with systemic steroid and dapsone. Clinicians should be aware that necrotizing eosinophilic folliculitis may occur after Rhus contact or consumption, in order to diagnose and treat patients promptly and reduce patient discomfort and skin scarring.

Superficial Granulomatous Pyoderma Gangrenosum Involving the Face: A Case Series of Five Patients and a Review of the Literature [Formula: see text]

BACKGROUND

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by painful and ulcerating lesions on the skin. It rarely involves the face and is often difficult to diagnose. There are few cases reported in the literature of PG involving the face.

AIM

To share our experience with 5 patients in whom the final diagnosis was PG involving the face, and to review the literature.

METHODS

We report a series of 5 patients with a final diagnosis of PG involving the face and reviewed relevant literature. We searched through PubMed andEMBASE using keywords such as "face" and "pyoderma gangrenosum," "blastomycosis-like pyoderma gangrenosum, vegetative pyoderma gangrenosum and granulomatous pyoderma gangrenosum."

RESULTS

We report 5 patients (4 females) with pyoderma gangrenosum involving the face. All 5 had a final diagnosis of superficial granulomatous PG. All cases presented with nonhealing facial ulcer most commonly on cheeks and a common histopathology of mixed inflammatory infiltrates, multinucleated giant cells, and plasma cells with some granulomatous inflammation.

CONCLUSIONS

PG can involve the face, and all 5 of our patients had the superficial granulomatous as the most common form.

Pyoderma gangrenosum

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that presents with rapidly developing, painful skin ulcers hallmarked by undermined borders and peripheral erythema. Epidemiological studies indicate that the average age of PG onset is in the mid-40s, with an incidence of a few cases per million person-years. PG is often associated with a variety of other immune-mediated diseases, most commonly inflammatory bowel disease and rheumatoid arthritis. The cause of PG is not well understood, but PG is generally considered an autoinflammatory disorder. Studies have focused on the role of T cells, especially at the wound margin; these cells may support the destructive autoinflammatory response by the innate immune system. PG is difficult to diagnose as several differential diagnoses are possible; in addition to clinical examination, laboratory tests of biopsied wound tissue are required for an accurate diagnosis, and new validated diagnostic criteria will facilitate the process. Treatment of PG typically starts with fast-acting immunosuppressive drugs (corticosteroids and/or cyclosporine) to reduce inflammation followed by the addition of more slowly acting immunosuppressive drugs with superior adverse event profiles, including biologics (in particular, anti-tumour necrosis factor (TNF) agents). Appropriate wound care is also essential. Future research should focus on PG-specific outcome measures and PG quality-of-life studies.

Histopathologic features of noninfectious granulomatous disorders involving the skin

Granulomatous dermatoses may represent primary skin inflammation or can serve as the harbinger of a multitude of underlying systemic disorders or drug reactions. Taken together with clinical findings, the microscopic features from skin biopsy can allow recognition of various patterns and facilitate a precise diagnosis. Accurate classification of entities in this category of inflammatory dermatoses may prompt clinicians to investigate for underlying systemic problems, thereby allowing the pathologist to add considerable value in the care of affected patients. This review article categorizes clinical and microscopic features of common and uncommon causes of noninfectious dermal and subcutaneous granulomatous inflammation.

Pyoderma gangrenosum - a guide to diagnosis and management

Pyoderma gangrenosum (PG) is a reactive non-infectious inflammatory dermatosis falling under the spectrum of the neutrophilic dermatoses. There are several subtypes, with 'classical PG' as the most common form in approximately 85% cases. This presents as an extremely painful erythematous lesion which rapidly progresses to a blistered or necrotic ulcer. There is often a ragged undermined edge with a violaceous/erythematous border. The lower legs are most frequently affected although PG can present at any body site. Other subtypes include bullous, vegetative, pustular, peristomal and superficial granulomatous variants. The differential diagnosis includes all other causes of cutaneous ulceration as there are no definitive laboratory or histopathological criteria for PG. Underlying systemic conditions are found in up to 50% of cases and thus clinicians should investigate thoroughly for such conditions once a diagnosis of PG has been made. Treatment of PG remains largely anecdotal, with no national or international guidelines, and is selected according to severity and rate of progression. Despite being a well-recognised condition, there is often a failure to make an early diagnosis of PG. This diagnosis should be actively considered when assessing ulcers, as prompt treatment may avoid the complications of prolonged systemic therapy, delayed wound healing and scarring.

Neutrophilic dermatoses: Pyoderma gangrenosum and other bowel- and arthritis-associated neutrophilic dermatoses

Neutrophilic dermatoses are a heterogeneous group of inflammatory skin disorders that present with unique clinical features but are unified by the presence of a sterile, predominantly neutrophilic infiltrate on histopathology. The morphology of cutaneous lesions associated with these disorders is heterogeneous, which renders diagnosis challenging. Moreover, a thorough evaluation is required to exclude diseases that mimic these disorders and to diagnose potential associated infectious, inflammatory, and neoplastic processes. While some neutrophilic dermatoses may resolve spontaneously, most require treatment to achieve remission. Delays in diagnosis and treatment can lead to significant patient morbidity and even mortality. Therapeutic modalities range from systemic corticosteroids to novel biologic agents, and the treatment literature is rapidly expanding. The second article in this continuing medical education series reviews the epidemiology, clinical characteristics, histopathologic features, diagnosis, and management of pyoderma gangrenosum as well as bowel-associated dermatosis-arthritis syndrome and the arthritis-associated neutrophilic dermatoses rheumatoid neutrophilic dermatitis and adult Still disease.

Pyoderma gangrenosum after breast surgery: A systematic review

BACKGROUND

Post-surgical pyoderma gangrenosum (PSPG) is a rare inflammatory skin disorder of unknown aetiology. Given its similar presentation to wound infection and lack of reliable diagnostic tests as well as pathognomonic clinical features, PSPG is difficult to diagnose. The aim of this review was to identify factors contributing to PSPG to aid with timely diagnosis and appropriate therapy.

METHODS

A systematic literature review was performed by following PRISMA guidelines, focusing on PSPG after reconstructive and aesthetic breast surgery. The online databases PubMed, Medline, EMBASE, Scopus, and Cochrane were used, and additionally, a Google^© search was performed.

RESULTS

A total of 68 articles describing 87 cases of PSPG following aesthetic and reconstructive breast surgery were found. The majority of PSPG (44%) occurred after breast reduction surgery and microsurgical breast reconstruction (16%). The most common associated conditions were malignancies in 37% and autoimmune deficiencies in 17%. Microbiological examinations were found to have a negative result in 90%. The median time from initial presentation with symptoms to correct diagnosis of PG was on average 12.5 days, with unsuccessful first-line therapy on average for 20.0 days. After the diagnosis of PG, medical therapy most commonly involved steroids in 84% and/or Cyclosporine A in 22% of the cases. On average, the duration of this therapy was 4.7 months.

CONCLUSION

The diagnosis of PSPG remains a challenging issue. However, according to the presented review, several distinct clinical signs in combination with lack of treatment response should prompt further investigation to promote timely diagnosis and correct treatment of this potentially debilitating disease.

Pulmonary nodules and nodular scleritis in a teenager with superficial granulomatous pyoderma gangrenosum

Superficial granulomatous pyoderma gangrenosum, a rare variant of pyoderma gangrenosum, has been considered to be the most benign form of the disease. We present the case of a 15-year-old boy with pulmonary involvement and nodular scleritis associated with this unusual type of pyoderma gangrenosum and discuss its differential diagnosis.

Pyoderma Gangrenosum: A Current Problem as Much as an Unknown One

Pyoderma gangrenosum (PG) is a rare neutrophilic inflammatory skin disease, characterized by recurrent skin ulcers, which in almost 50% of cases are associated with systemic autoimmune disorders, including rheumatoid arthritis, chronic hepatitis, inflammatory bowel disease, paraproteinemias and hematological malignancies. A systematic search of literature for PG was carried out using the PubMed, Embase, and Google Scholar databases for the purpose of this review and 2780 articles were retrieved up to February 2017. Inflammation represents the predominant aspect of the disease, but its pathophysiological mechanisms are not completely clear yet, since there are many studies showing only one or more isolated findings of the disease. The goal of PG treatment is to reduce inflammation in order to promote ulcer healing by minimizing side effects of therapy. Several systemic and local treatments are available, but the lack of large randomized double-blind studies results in an absence of a uniform therapeutic standard: thus, more clinical studies are required in order to make head-to-head comparisons between combination and single-drug therapies and to identify specific combination therapies for distinctive clinical patterns of PG.

Clinical and histopathological features of cutaneous nontuberculous mycobacterial infection: a review of 13 cases

BACKGROUND

The incidence of cutaneous nontuberculous mycobacterial (NTM) infection has increased in recent decades because of widespread use of immunosuppressive therapy and better detection methods. The histopathology of cutaneous NTM infection is not pathognomic and the organisms are slow and difficult to culture, making diagnosis challenging.

METHODS

We reviewed the clinical and histopathological features of 13 cases of cutaneous NTM infection, and performed panmycobacterial polymerase chain reaction (PCR) on the paraffin blocks.

RESULTS

The immunocompetent patients presented with localized lesions on the extremities, whereas the immunocompromised patients presented with disseminated cutaneous lesions. The histopathology in immunocompetent patients was characterized by pseudoepitheliomatous epidermal hyperplasia, intraepithelial abscesses, transepidermal elimination and dermal granulomatous inflammation accompanied by necrosis and suppuration. The immunocompromised patients showed suppurative inflammation with little granuloma formation and numerous acid-fast bacilli. Paraffin block PCR was positive in 4 of 13 cases (31%), whereas culture was positive in 11 of 13 cases (85%).

CONCLUSION

The aforementioned histological features should help in diagnosing cutaneous NTM infection when combined with clinical and microbiological correlation. In our study, we did not find paraffin block PCR to be superior to conventional culture in detecting cutaneous NTM infection.

Pyoderma Vegetans

Background:

Pyoderma vegetans is a rare condition that is clinically characterized by large verrucous plaques with elevated borders and multiple pustules. The etiology of this disorder remains unknown.

Objectives:

We describe a 24-year-old woman with rapidly evolving pyoderma vegetans. Our patient had the unique additional findings of a highly elevated serum IgE level and a history of hidradenitis suppurativa.

Conclusions:

Pyoderma vegetans is diagnosed on clinical and histological criteria. Differentiation must be made from disorders such as pyoderma gangrenosum, Sweet's syndrome, and deep fungal infections. We illustrate a case of pyoderma vegetans and review the literature on this rare disorder. Clinical and histological criteria for diagnosis are presented, as well as differentiation from some mimicking disorders.

Postoperative Pyoderma Gangrenosum: A Clinical Review of Published Cases

Postoperative pyoderma gangrenosum (PG) is a neutrophilic dermatosis characterized by PG at surgical incisions. It is often misdiagnosed as wound infection, and pathergy may complicate wound debridement. From September 1, 2013, through November 30, 2013, a literature search was conducted of articles published from January 1, 1978, through December 31, 2012. We referenced PubMed, MEDLINE, and Mayo Clinic Libraries using the keywords pyoderma gangrenosum, postoperative pyoderma gangrenosum, postsurgical pyoderma gangrenosum, superficial granulomatous pyoderma, pathergic pyoderma, and pyoderma gangrenosum associated with surgery, incision, breast, and wound dehiscence. In addition, all titles from PubMed with the words pyoderma gangrenosum were reviewed manually for postoperative cases. Of 136 patients, 90 (66%) did not have associated systemic diseases. If a comorbidity was present, hematologic disorders were most common. In addition, 29% (28) of women had predisposing disease vs 53% (19) of men. Women had more frequent breast involvement (P<.001); chest involvement was more common in men (P=.005). Girls and women aged 13 to 64 years had more frequent breast involvement (P=.01). Sites were distributed equally for men regardless of age (P=.40). Antibiotic drug therapy was begun and debridement occurred in 90% (110 of 122 treated patients) and 73% (90 of 123 available patients), respectively. Postoperative PG has less association with systemic disease than its nonpostoperative counterpart. Antibiotic drug therapy is routinely initiated. Affected sites are often debrided, causing additional wound breakdown. Early diagnosis may prevent complications.

Pyoderma gangrenosum and Sweet syndrome: the prototypic neutrophilic dermatoses

Pyoderma gangrenosum, a dramatic ulcerative skin disease, and Sweet syndrome, a papular dermatosis, were described independently. It was subsequently shown that they share many characteristics, including clinical overlap and the frequent association with multisystemic disorders. The group of the neutrophilic dermatoses encompasses these two dermatoses, as well as other conditions having in common an aseptic neutrophilic infiltrate predominating in the epidermis and/or the dermis and/or the subcutis. Some patients also experience neutrophilic infiltrates in other organs, defining the neutrophilic disease. Recent research suggests that the neutrophilic dermatoses could be considered as the cutaneous expression of the autoinflammation, an aberrant hyperproduction of interleukin-1. Autoinflammation is responsible for monogenic diseases, and is also involved in the mechanism of many polygenic conditions, including the neutrophilic dermatoses.

Granulomatous pyoderma gangrenosum of the genitalia in the absence of Crohn's disease

Pyoderma gangrenosum (PG) is a rare ulcerative neutrophilic disorder of the skin. Atypical variants of PG such as vegetative PG, bullous PG, and pustular forms are described in literature. Occasionally, granulomatous reaction in dermis may be seen on histology when PG is associated with Crohn's disease or in the vegetative variant of PG. We report a case of granulomatous PG involving the genitalia in a 43-year-old female without associated inflammatory bowel disease.

Pyoderma gangrenosum: a review of clinical features and outcomes of 23 cases requiring inpatient management

Pyoderma gangrenosum (PG) is a rare dermatological disorder characterised by the rapid progression of a painful, necrolytic ulcer. This study retrospectively identified patients who were admitted and treated for PG during a 10-year period (2003–2013). Twenty-three patients were included in this study, 16 women and seven men. The mean age at initial admission was 62.8 years (range 30 to 89 years). Lesions were localised to lower limb in 13 patients, peristomal region in four, breast in three, and upper limb in one, and two patients had PG at multiple sites. The variants of PG noted were ulcerative (18), bullous (2), vegetative (2), and pustular (1). Associated systemic diseases were observed in 11 patients (47.8%). Systemic therapies were initiated in 21 patients while two patients received topical treatments. The mean length of hospital stay was 47 days (range 5 to 243 days) and five patients died during their admissions. Seven patients required readmissions for exacerbations of their PG. Our study showed that patients admitted for treatment of PG had high morbidity and mortality. This study also highlights the importance of early and aggressive treatment of patients admitted with PG as well as treating associated systemic diseases and wound infections.

Autoinflammatory skin disorders in inflammatory bowel diseases, pyoderma gangrenosum and Sweet's syndrome: a comprehensive review and disease classification criteria

Pyoderma gangrenosum (PG) and Sweet's syndrome (SS) are skin diseases usually presenting with recurrent ulcers and erythematous plaques, respectively. The accumulation of neutrophils in the skin, characteristic of these conditions, led to coin the term of neutrophilic dermatoses to define them. Recently, neutrophilic dermatoses have been included in the group of autoinflammatory diseases, which classically comprises genetically determined forms due to mutations of genes regulating the innate immune response. Both PG and SS are frequently associated with inflammatory bowel diseases (IBDs); however, IBD patients develop PG in 1-3 % of cases, whereas SS is rarer. Clinically, PG presents with deep erythematous-to-violaceous painful ulcers with well-defined borders; bullous, pustular, and vegetative variants can also occur. SS is characterized by the abrupt onset of fever, peripheral neutrophilia, tender erythematous skin lesions, and a diffuse neutrophilic dermal infiltrate. It is also known as acute febrile neutrophilic dermatosis. Treatment of PG involves a combination of wound care, topical medications, antibiotics for secondary infections, and treatment of the underlying IBD. Topical therapies include corticosteroids and the calcineurin inhibitor tacrolimus. The most frequently used systemic medications are corticosteroids and cyclosporine, in monotherapy or in combination. Dapsone, azathioprine, cyclophosphamide, methotrexate, intravenous immunoglobulins, mycophenolate mofetil, and plasmapheresis are considered second-line agents. Hyperbaric oxygen, as supportive therapy, can be added. Anti-TNF-α agents such as etanercept, infliximab, and adalimumab are used in refractory cases. SS is usually responsive to oral corticosteroids, and the above-mentioned immunosuppressants should be considered in resistant or highly relapsing cases.

A challenging diagnosis: case report of extensive pyoderma gangrenosum at multiple sites

BACKGROUND

Pyoderma gangrenosum (PG) is a rare dermatological condition characterized by the rapid progression of a painful, necrolytic ulcer with an irregular, undermined border and commonly affects the lower extremities, mainly in the pretibial area. The diagnosis of PG is not easy. Due to lack of diagnostic laboratory test and histopathological findings indicative of PG, it is often misdiagnosed as an infection. This results in delayed or inappropriate treatment of the condition, which leads to devastating consequences such as limb amputation and death.

MAIN OBSERVATIONS

We report a rare case of a 51-year-old female who was initially diagnosed as having infected ulcers and underwent serial debridements, which resulted in extensive PG at three different sites (abdominal, left thigh, and sacral).

CONCLUSION

This case highlights the challenges in diagnosing PG, emphasizes the key clinical features to aid diagnosis, and the clinical consequences of delayed or misdiagnosis of this condition.

[The modern concepts of pyoderma gangrenosum]

The review provides an update on pyoderma ganrenosum, a rare chronic disease from a group of neutrophilic dermatoses. It considers its pathogenesis, its association with background visceral disease, and the specific features of skin and visceral involvement. Major and minor diagnostic criteria and differential treatment approaches are given.

Neutrophilic dermatoses as systemic diseases

Neutrophilic dermatoses (ND) are inflammatory skin conditions characterized by a sterile infiltrate of normal polymorphonuclear leukocytes. The main clinical forms of ND include Sweet syndrome, pyoderma gangrenosum, erythema elevatum diutinum, subcorneal pustular dermatosis, and their atypical or transitional forms. ND are often idiopathic, but they may be associated with myeloid hematologic malignancies (Sweet syndrome), inflammatory bowel disease or rheumatoid arthritis (pyoderma gangrenosum), and monoclonal gammopathies (erythema elevatum diutinum, subcorneal pustular dermatosis). The possible infiltration of internal organs with neutrophils during the setting of ND underlies the concept of a neutrophilic systemic disease. ND may be seen as a polygenic autoinflammatory syndrome due to their frequent association with other autoinflammatory disorders (monogenic or polygenic) and the recent published efficacy of interleukin-1 blocking therapies in their management.

Etiology and management of pyoderma gangrenosum: a comprehensive review

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by painful, necrotic ulceration. It typically affects patients in the third to sixth decades of life, with almost equal incidence in men and women. PG occurs most frequently on the lower extremities. Five clinical variants are currently recognized: classic, bullous, pustular, vegetative, and peristomal types. Half of PG cases are seen in association with systemic disease. Mimickers include infection, vascular insufficiency ulcers, systemic vasculitides, autoimmune disease, cancer, and exogenous tissue injury, among others. PG is often a diagnosis of exclusion, as there are no specific laboratory or histopathologic findings to confirm the diagnosis. PG thus presents many clinical challenges: it is difficult to diagnose, is frequently misdiagnosed, and often requires a work-up for underlying systemic disease. Successful management of PG typically requires multiple modalities to reduce inflammation and optimize wound healing, in addition to treatment of any underlying diseases. Prednisone and cyclosporine have been mainstays of systemic treatment for PG, although increasing evidence supports the use of biologic therapies, such as tumor necrosis factor-α inhibitors, for refractory cases of PG. Here, we review the clinical presentation and pathophysiology of PG, as well as its associated conditions, diagnostic work-up, and management.