When A Chronic, Painful Wound Is Actually Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is a rare inflammatory skin condition that is difficult to diagnose. Currently, it is a "diagnosis of exclusion."¹ Presentation of a patient with a red, hot, swollen foot, ankle or leg is not uncommon for the foot and ankle provider, however, misdiagnosis and delayed diagnosis are common in cases of PG. In a retrospective study, 39 percent of patients who initially received a diagnosis of PG were ultimately found to have a prior alternate diagnosis.¹

Part of the difficulty for the foot and ankle provider is that prior to 2018, there was not a clear path for diagnosis or treatment of this condition. In 2018, a committee of wound care experts formed a consensus to delineate and diagnose ulcerative pyoderma gangrenosum. We have since gained a criterium from the Delphi Consensus that helps the clinician focus on major and minor criteria within the patient's presentation.¹ According to the Delphi Consensus, the major criteria is a biopsy showing neutrophilic infiltrates with extending necrosis.¹ Minor criteria may include: exclusion of infection; hyperreactivity of the skin in response to minor trauma (pathergy); inflammatory bowel disease or inflammatory arthritis; peripheral erythema; increased necrosis; pain at the ulcer site; decrease in size of the ulcer with immunosuppressive therapy; multiple ulcerations with the primary ulceration noted on the anterior region of the distal leg; or a prior healed contracted (cribriform) scar.¹

When a patient presents for emergent care with PG, they often receive a diagnosis of venous stasis with associated wounds.² At the same time, others may be diagnosed with a form of vasculitis or even undergo ultrasound to rule out deep vein thrombosis (DVT). After reviewing the Delphi Criteria, we can better understand that previous care was likely well-intended. However, a diagnosis of ulcerative pyoderma gangrenousum is often overlooked or at the bottom of the differential diagnosis list.¹

When A Patient Presents For An Additional Opinion On Chronic Wounds

We recently had the opportunity to care for a patient who had received care at a wound care center for two years. Upon his presentation to our facility, he stated he would like a second opinion as the wounds constantly remained painful, the size would fluctuate from small to large and the redness around the wound was a constant. The patient was a 61-year-old male with type 2 diabetes who presented with bilateral 3+ pitting lower extremity edema with an extensive history of venous stasis care. In his previous treatment plan, the patient received bilateral multilayer compression dressings, advanced wound healing modalities along with fibroblast amnion dressings and minor sharp debridements.

Upon meeting the patient, we performed an extensive review of his past medical history. We specifically noted the absence of a cardiac workup and no echocardiogram on file. Furthermore, the patient was not on any diuretic medication to help alleviate the fluid load. After the initial meeting, we ordered labs, a cardiac consult to include an echocardiogram, and started diuretic medication. Given the sickly presentation of the patient, an in-depth review of the labs was carried out prior to the podiatry team starting the patient on 20 mg of furosemide with 10 meq of potassium. Hypokalemia and possible heart arrhythmias are ever-present concerns when prescribing loop diuretics as part of the therapy.  Additionally, we advised compression therapy to treat the advanced edematous presentation.

Upon follow-up, we noted large bullae over the right medial and lateral pretibial areas that had begun to ulcerate. When questioned about the formation of the bullae, the patient stated he had accidentally run into the trailer hitch on the back of his vehicle. The patient stated he did not think much about the injury at the time and he felt fine. Local wound care at that time included sharp debridement, wet-to-dry dressings and continued compression. We provided education to the patient regarding signs and symptoms of infection, counseling him to call the office if these arose or his condition worsened.

Formulating A Plan Of Care: What You Should Know

The patient followed up two weeks later for continued care. The bullae over the medial and lateral pretibial area had converted into deep, necrotic-type wounds with a violaceous, erythematous peri-wound halo. Given the profound change in the patient's presentation in such a short amount of time, we again performed debridement to avoid fibrotic tissue building up in the base of the wound. We also obtained biopsies from multiple locations within the wound base to rule out any sampling errors. Biopsy results revealed the presence of neutrophilic infiltrate. Given the history and onset of the presentation and the biopsy results, we suspected he indeed had ulcerative pyoderma gangrenosum. Given this, we decided to withhold usage of compressive dressings due to predisposition to advancing the necrotizing ulceration in the face of pathergy. Advanced treatment included sharp debridement to alleviate the wound base's fibrotic tissue burden, with acetic acid irrigation. Historically, some providers have used saline to irrigate wounds. The author favors irrigation with acetic acid in anticipation of treating pseudomonal overgrowth as PG wounds tend to be highly exudative with large amounts of drainage and colonization of Pseudomonas aeruginosa. By lowering the Ph of the wound environment with acetic acid, the provider is better able to treat colonization of bacteria and avoid a polymicrobial infection. According to the literature, we used the patient's weight in kilograms to calculate a scheduled course of prednisone.³ Skin-safe tape affixed the dressing to the limb in place of compression. We also started the patient on prophylactic Augmentin given the broad nature of the antibiotic coverage.

The patient returned to the clinic one week later and showed progress. The edema had started to subside, the necrotic nature of the bullae had started to convert into a fibrotic tissue that was much easier to sharply debride. The previously noted erythema had improved. Overall, the patient stated he "was feeling much better." At this visit, we again chose to forgo the compressive multilayer wraps that are so common for treating venous stasis ulcerations and edema. The patient continued his furosemide therapy, prednisone and elevation. Given the newly started medications and concern for the patient's kidneys, we ordered follow-up labs to ensure the patient tolerated the new therapies.

Each week the patient’s presentation continued to improve. With steady, high-quality and problem-focused wound care, the necrotic-type ulceration started to heal and show steady improvement. Given the diagnosed pyoderma gangrenosum, we fully expected the wound to become highly exudative and prophylactically applied skin barrier cream to the edges of the peri-wound skin for protection. As the patient continued his care the wound exudate became so extensive, on occasion, ABD pads were added to the dressing to avoid the drainage from striking through. With the continued furosemide therapy, prednisone and sharp debridements, the patient continued to show progress toward healing. The patient was fully healed 12 weeks after the initial biopsy results and proper diagnosis. The patient continues to visit our clinic for ongoing care and maintenance of his bilateral limbs.

In Conclusion

When treating patients with advanced wounds, differential diagnosis should include pyoderma gangrenosum. Pyoderma gangrenosum is a challenging pathology to diagnose and treat. With continued patient education and proper steps to treating the underlying causes, the patient can show improvement, as demonstrated in the discussed case. Imperative things to remember include: controlling the edema; managing the inflammation; and utilizing proper debridement skills. Obtaining a biopsy should take place early on in the treatment of suspected pyoderma gangrenosum. These clinical practices could make a difference in quality of care, healing time and overall outcomes.   

Dr. Bland is a fellowship-trained, board certified foot and ankle surgeon in practice in Phoenix, Ariz.

Dr. Trevino is Chief Resident at St. Joseph Medical Center in Houston, Tx.

Ms. Aldaz has extensive wound care background and will be a family practice NP at the end of the year in Phoenix, Ariz.

1. Maverakis E, Ma C, Shinkai K, et al. Diagnostic criteria of ulcerative pyoderma gangrenosum. JAMA Dermatol. 2018;154(4):461-466.

2. Croitoru D, Naderi-Azad S, Sachdeva M, Piguet V, Alavi A. A wound care specialist's approach to pyoderma gangrenosum. Adv Wound Care. 2020;9(12):686–694. h

3. Ormerod AD, Thomas KS, Craig FE, et al. Comparison of the two most commonly used treatments for pyoderma gangrenosum: results of the STOP GAP randomized controlled trial. BMJ. 2015;350:1–8.