Infective Panniculitis

Neutrophilic Panniculitides

Neutrophilic panniculitides are a heterogeneous group of inflammatory disorders encompassing many different entities. This review article focuses on the epidemiology, pathogenesis, clinicopathological features, diagnosis, and treatment of selected diseases. Patients often seek care due to systemic involvement, but the variable presentation of panniculitides can present a diagnostic challenge. Most therapeutic modalities for neutrophilic disorders are anecdotal at best with a notable lack of standardization of the responses to medications. There is an urgent need for a larger multi-institutional collaboration to address the unmet needs of these challenging, yet rare conditions.

Pseudomonas aeruginosa as an uncommon agent of infectious panniculitis

Pseudomonas aeruginosa is a Gram-negative bacillus that frequently causes septicemia, abscesses and infections in skin wounds. Panniculitis caused by this microorganism is unusual and there are few well-documented cases, none of them in a patient with systemic lupus erythematosus. The present report describes an immunosuppressed patient with systemic lupus erythematosus who developed panniculitis caused by Pseudomonas aeruginosa, with a review of the literature on this rare presentation.

Methicillin-resistant Staphylococcus aureus (MRSA) panniculitis in a patient undergoing stem cell mobilisation

Methicillin-resistant Staphylococcus aureus (MRSA) can cause a wide range of skin infections, however MRSA panniculitis without bacteremia is a rare manifestation. Here, we report a woman in her 20s with relapsed Hodgkin lymphoma undergoing stem cell mobilisation who presented with bilateral subcutaneous nodules over her shins. Ultrasound scan of one nodule showed non-specific inflammatory changes. Punch biopsy of a nodule showed lobular panniculitis with Gram-positive cocci. Blood cultures were negative but a culture from the biopsy grew MRSA. She was started on doxycycline with improvement in her symptoms. This case serves as a reminder to consider infections as a cause of panniculitis in immunocompromised patients.

Viral panniculitis in a patient with disseminated opportunistic Enterovirus infection

Infection-induced panniculitis has been described in association with a broad range of microorganisms. Among those, viral panniculitis represents a minor category, with only a few anecdotal reports in the literature documenting viral infection in the subcutaneous fat. Herein, we report a woman in her 30s with seropositive rheumatoid arthritis on rituximab and prednisone, who presented with a 6-month history of progressive multisystem manifestations, including unintentional weight loss, fever, fatigue, myopathy, pancreatitis, and sensorineural hearing loss. She had indurated plaques on her thighs characterized by predominantly lobular panniculitis with chronic lymphohistiocytic inflammation. Molecular studies performed at the Centers for Disease Control and Prevention identified evidence of Enterovirus group with the highest identity of Coxsackievirus A9. Enterovirus RNA was also detected in the cerebrospinal fluid and muscle. Based on the findings, a diagnosis of disseminated enteroviral infection in the setting of B-cell depletion was rendered. To the best of our knowledge, this represents the first reported case of viral panniculitis with documentation of Coxsackievirus A9 in the skin. Since rituximab may be used for the treatment of autoimmune dermatological diseases, familiarity of the potential occurrence of severe enteroviral infections in the setting of immunosuppressive treatment is important for dermatopathologists.

Panniculitis: A summary

The diagnosis of panniculitis is felt to be a confusing topic by some pathologists. This summarical article presents inflammatory diseases of the subcutis in a systematic fashion, based on whether they are centered on fibrovascular septa or the adipose lobules, and whether morphologic vasculitis is present or not. Septocentric, non-vasculitis disorders include erythema nodosum, panniculitis that follows the use of "biological" therapeutic agents, lipodermatosclerosis, post-irradiation panniculitis, morphea profunda, and necrobiosis lipodica profunda. Polyarteritis nodosa and Behçet's disease are the conditions that are based in the subcutaneous septa with vasculitis. Predominantly-lobular panniculitides with no vasculitis include pancreatogenic panniculitis, the panniculitis of alpha-1-antitrypsin deficiency, panniculitis associated with lupus erythematosus and dermatomyositis, subcutaneous Sweet syndrome, eosinophilic panniculitis, factitial panniculitis, cold panniculitis, panniculitis following injections of corticosteroids, lipomembranous (ischemic) panniculitis; sclerema neonatorum and subcutaneous fat necrosis of the newborn, and Rosai-Dorfman disease of the subcutis. Erythema induratum and infectious panniculitis are vasculitic and lobulocentric conditions. This article reviews the histological features of these diseases.

Neutrophilic panniculitis: algorithmic approach to a heterogeneous group of disorders

CONTEXT

Neutrophilic panniculitis encompasses an etiologically and morphologically heterogeneous group of disorders. Correct histopathologic diagnosis is important in identifying certain systemic diseases and guiding appropriate treatment.

OBJECTIVE

To review the clinical and histopathologic features of different types of neutrophilic panniculitis, and to provide a diagnostic algorithm for these disorders.

DATA SOURCES

A review of the literature with emphasis on the distinguishing features of different entities was performed.

CONCLUSIONS

Evaluation for neutrophilic panniculitis entails paying close attention to the pattern of inflammation, the type of fat necrosis present, any evidence of vascular damage, and other relevant histopathologic features. An algorithmic approach integrating all histopathologic, clinical, and laboratory findings is required for correct diagnosis.

Successful Treatment of Infective Panniculitis With Daptomycin in a Pregnant, Morbidly Obese Patient

Objective: To report a case of infective panniculitis in a morbidly obese, pregnant woman, which was successfully treated with daptomycin. Case Summary: A 34-year-old, 27-week pregnant, morbidly obese woman with a history of skin/soft-tissue infections and diabetes mellitus, presented with panniculitis. Initial treatment with β-lactam antibiotics did not result in clinical improvement. Methicillin-resistant Staphylococcus aureus was suspected, and 14 days of daptomycin 4 mg/kg (using total body weight) resulted in a clinical cure, without any adverse effects on the mother or the neonate. Discussion: Panniculitis is a type of skin/soft-tissue infection that is often caused by Gram-positive microorganisms. Daptomycin is one of the recommended agents for the treatment of skin/soft-tissue infections in hospitalized patients; however, it has not been extensively studied in pregnancy or morbid obesity. Some data suggest that exposure to daptomycin is significantly increased in morbidly obese persons because of the higher total dose received in this patient population. Animal data suggest that this drug is safe in pregnancy (category B), and at the time of publication, 3 prior cases of safe use of daptomycin in pregnancy have been reported. Conclusions: This case provides additional evidence for the use of daptomycin in pregnancy as well as morbid obesity.

Histoplasmosis and subcutaneous nodules in a kidney transplant recipient: erythema nodosum versus fungal panniculitis

Erythema nodosum (EN)-like lesions are a rare occurrence after solid organ transplantation. Differential diagnosis includes infective panniculitis, which can be a feature of progressive disseminated histoplasmosis (PDH), an uncommon but severe form affecting primarily immunocompromised hosts. We report on a fatal case of PDH, which presented as fungal panniculitis masquerading as EN in a renal allograft recipient 25 years after transplantation. We discuss the clinical, histopathological, and microbiological characteristics of this rare complication, with focus on its distinction from EN. This case emphasizes the central role of biopsy in transplant recipients presenting with cutaneous lesions, and the importance of clinicopathologic correlation and complementary microbiological investigations.

Infection and panniculitis

Infection-induced panniculitis may result from a number of microbes including bacteria, fungi, and parasites. Viruses have also been implicated as a cause. This type of panniculitis can occur as a primary infection by direct inoculation of infectious microorganisms into the subcutaneous tissue, or secondarily via microbial hematogenous dissemination with subsequent infection of the subcutaneous tissue. Panniculitis is rarely viewed solely in terms of infectious causes. Also, subcutaneous infections are infrequently viewed in terms of infection-induced panniculitis but rather as cutaneous infections with subcutaneous involvement. Little information exists specifically on the subject of infection-induced panniculitis outside of the realm of case reports and case series. In this review, the present authors address panniculitis from the vantage point of infectious causes, focusing on those microorganisms with infection-induced panniculitis reports in the literature. Diagnosis and treatment are also discussed.