Pyoderma gangrenosum is a rare but serious ulcerating skin disease causing painful ulcers on the legs and other parts of the body. Although pyoderma gangrenosum can affect individuals of any age, it is most common in people in their 40s and 50s. It tends to be associated with inflammatory conditions, including ulcerative colitis, Crohn's disease, rheumatoid arthritis, and hepatitis.

Diagnosis of pyoderma gangrenosum can be problematic as no specific diagnostic features can be identified from biopsies and no laboratory marker is available. Diagnosis is therefore generally based on clinical findings and through the exclusion of other possible disorders. To improve accuracy of diagnosis, it is important to have a thorough understanding of the patient’s medical history so that risk factors for pyoderma gangrenosum may be identified.(1-3)

Differential diagnosis

There are five common disease categories which may imitate the appearance of pyoderma gangrenosum.(1) Ruling out any of these conditions can point to a diagnosis of pyoderma gangrenosum.

•          Infections –  bacterial, mycobacterial, fungal, viral, parasitic

•          Malignancy –  squamous cell carcinoma, cutaneous lymphoma

•          Vascular ulceration –  venous or arterial disease, antiphospholipid syndrome

•          Systemic conditions –  systemic lupus erythematosis, rheumatoid arthritis, Behçet’s disease, Wegner’s granulomatosis

•          Sweet’s syndrome

Sweet’s syndrome, characterized by the sudden onset of fever and an erythematous, papular eruption, in particular can be hard to differentiate from pyoderma gangrenosum. Sweet’s syndrome and pyoderma can coexist in the same patient as they are both neutrophilic dermatoses.(1)

Because the diagnosis  of pyoderma gangrenosum can be so challenging, and because the consequences of a late or missed diagnosis can be so devastating, it is worth developing a good understanding of the signs of this condition, particularly among patients with inflammatory disorders.  The opportunity to study conditions such as pyoderma gangrenosum in greater depth can be gained by pursuing additional professional development, including wound certification. For more information on the benefits of wound care certification, please visit www.woundeducators.com.

References

1.         Brooklyn T, Dunnill G, Probert C. Diagnosis and treatment of pyoderma gangrenosum. BMJ. 2006;333:181-4.

2.         Wollina U. Pyoderma gangrenosum--a review. Orphanet J Rare Dis. 200715;2:19.

3.         Jackson M, Callen JP. Pyoderma gangrenosum.  Medscape March 2010 (available at http://emedicine.medscape.com/article/1123821-overview#a0199).