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Pustular pyoderma gangrenosum

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Pustular pyoderma gangrenosum
Marie Leger MD PhD, Tracey Newlove MD, Julie Chu MD, Shane Meehan MD, Jennifer Stein MD PhD
Dermatology Online Journal 17 (10): 17

Department of Dermatology, New York University, New York, New York


A 79-year-old woman was admitted to our hospital with pustular pyoderma gangrenosum and an associated IgG kappa monoclonal gammopathy. The patient is currently being evaluated for possible multiple myeloma. IgG multiple myeloma and IgG monoclonal gammopathies are very rare in patients with pyoderma gangrenosum. The skin lesions are improving with the use of prednisone.


A 76-year-old woman was admitted to the New York University Langone Medical Center in January, 2011, for administration of antibiotics and debridement of a large, painful ulcer on the lateral aspect of the left leg. The ulcer began as a pimple in August, 2010, and became larger. The patient was treated with multiple courses of antibiotics and debridements prior to admission, but the ulcer continued to enlarge. All previous tissue cultures were negative. The dermatology service was consulted regarding the etiology of the ulcer as well as for the evaluation of several, new, slightly tender pustules on her left forearm, right scalp, and right thigh. Past medical history included only hypertension. She denied nausea, vomiting, fevers, chills, or diarrhea, but did report constipation that was associated with her pain medication. She also denied risky sexual behavior and denied a history of treated syphilis. Doxycycline was started, but the pustules on the medial aspect of the right thigh continued to increase and the nodule on her left forearm developed into a large, abscess-like pustular lesion. She also developed new lesions on the posterior aspects of the thighs. After the skin biopsy results were obtained, the patient was started on prednisone 60 mg daily. She was evaluated in the Charles C. Harris Skin and Cancer Pavilion approximately one week after discharge; there was improvement of the lesions on her right thigh, left forearm, and right breast, and no new lesions. A gastrointestinal evaluation and further hematologic evaluation are pending.

Physical examination

Figure 1Figure 2

There is a large, medium-depth ulcer with an erythematous, violacious border on the anterior, lateral, and posterior aspects of the left leg, with a dry and fibrinous adherent exudate. There is an erythematous nodule on left forearm, a tender erythematous papule on the right breast, and three pustules on the medial aspect of the right thigh. A hemorrhagic crust with a purulent base is noted on the right temporal portion of the scalp.

Laboratory data

The erythrocyte sedimentation rate was 91 mm/hr, C-reactive protein >90 mg/ml, and white-cell count 12.2 x 109/L with 66 percent neutrophils. The fluorescent treponemal antibody absorption test was positive and the rapid plasma regain test was negative. An IgG kappa monoclonal gammopathy was present. Neutrophil cytoplasmic antibodies (p-ANCA, c-ANCA), antinuclear antibodies, and rheumatoid factor were negative. A culture of the scalp pustule, blood cultures, hepatitis B antigen, and hepatitis C antibody were negative.


Figure 3

There is an ulcer, beneath which is a dense and diffuse, predominantly neutrophilic infiltrate. Prominent fibrinoid necrosis is noted that involves many thin-walled blood vessels throughout the dermis.


Pyoderma gangrenosum (PG) is a chronic, recurrent, neutrophilic dermatosis that frequently is associated with systemic disease. Four clinical variants are commonly described. Ulcerative PG consists of painful ulcers with characteristic violaceous, undermined borders that develop rapidly from pustules or nodules and sometimes after trauma. Bullous PG begins with painful, tense, single or clustered bullae that rapidly ulcerate. The vegetative type is chronic, less aggressive, associated with superficial ulcers, and less frequently associated with systemic disease than are the other subtypes. Pustular PG consists of tender, sterile pustules that develop, usually in association with inflammatory bowel disease [1, 2]. This form is rare and can be difficult to diagnose [3]. Usually patients present with only one form of PG although more than one clinical type can be present in a single patient [4, 5]. Pathergy can worsen the lesions, as was noted in our patient.

It is reported that between 50 percent and 70 percent of patients with PG have an associated systemic condition, most commonly inflammatory bowel disease, arthritis, spondylytis, and rheumatoid arthritis. Hematologic diseases, which include acute and chronic myelogenous leukemia, myelodysplasia, and a monoclonal gammopathy generally of the IgA type, may be associated with PG. PG associated with an IgG monoclonal gammopathy is very rare. There have only been a few instances of PG associated with IgG κ or IgGλ multiple myeloma or an IgG plasmocytoma [6, 7, 8, 9]. Similarly, there are only a few cases of PG and an IgG paraproteinemia [10-15].

A stepwise approach to treating pyoderma gangrenosum, in which lesions are first controlled with high-dose glucocorticoids (1 to 3 mg/kd/day), has been described [4]. Usually four to six weeks of glucocorticoid therapy are needed [16]. Glucocorticoid sparing agents, most commonly dapsone or minocycline, can be added, if needed, to successfully taper the glucocorticoids. Cyclosporine can be an effective alternative to prednisone and it has been successfully used in combination with myophenolate mofetil [17]. Other agents that have been successfully implemented as glucocorticoid-sparing agents include azathioprine [2, 18], tacrolimus, mycophenolate mofetil, methotrexate, chlorambucil, and clofazimine. Tumor necrosis factor-α inhibitors, such as adalimumab or infliximab, have been shown to be helpful with refractory disease, especially in patients with inflammatory bowel disease [19, 20]. Intralesional glucocorticoids and topical tacrolimus also have been shown to be of value [21]. When associated with multiple myeloma, thalidomide and melphalan have been useful [4].

Pyoderma gangrenosum associated with multiple myeloma can resolve after treatment of the underlying myeloma [6, 8]. A patient with IgGκ paraproteinemia achieved resolution of the ulcers after treatment with glucocorticoids [13]. Another improved after receiving melphalan but subsequently relapsed [12]. A case report of one young patient with an IgA-λ monoclonal gammopathy, which was refractory to treatment with glucocorticoids, chemotherapy, and thalidomide, resolved after a peripheral blood stem-cell transplantation [22].

Our patient had a positive fluorescent treponemal antibody absorption test (FTA-ABS) test and a negative rapid plasma regain test (RPR). Owing to our patient’s denial of a history of treated syphilis, lack of typical clinical presentation, absence of neurologic symptoms, and absence of syphilis pathology, this result was consistent with a false positive FTA-ABS. When the FTA-ABS test is used as a screening test rather than as a confirmatory test (of a positive RPR or in the presence of signs/symptoms consistent with late syphilis), its positive predictive value is decreased. Cases of falsely elevated FTA-ABS have been reported in patients with monoclonal gammopathies [23].


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