Pyoderma gangrenosum - Cellulitis
Though the exact cause is unknown, PG has associations with a number of systemic illnesses. In about 50% of cases, there is an association between PG and systemic diseases such as ulcerative colitis, Crohn's disease, arthritis, myeloma, leukemia, monoclonal gammopathy, granulomatosis with polyangiitis, collagen vascular disease, Behçet's disease, and many other disorders. There is no racial or sex predilection. The disease occurs most often in middle-aged adults. PG tends to be self-limited, and although first-line therapies are widely accepted, alternative therapeutic recommendations are largely based on anecdotal evidence. Surgical intervention is a common exacerbating factor because skin trauma can lead to worsening disease. PG can have either an acute or chronic course and result in extensive scarring.
L88 – Pyoderma gangrenosum
74578003 – Pyoderma gangrenosum
- Infectious causes of ulcers can mimic PG. PG is in the family of neutrophilic skin disorders, which includes Sweet's syndrome, subcorneal pustular dermatosis, and Behçet's disease. As many infectious processes can cause a similar picture (eg, progressive bacterial synergistic gangrene, North American blastomycosis, other deep fungal infections, amebiasis, sporotrichosis, atypical mycobacterial infection), pyoderma gangrenosum is a diagnosis of exclusion.
- Calciphylaxis – Rapidly progressive, can be associated with eschars.
- Eosinophilic granulomatosis with polyangiitis
- Herpes simplex virus (HSV) – Usually grouped, punched-out erosions.
- Ecthyma gangrenosum
- Factitial ulcer – Sharp geometric borders.
- Factitial panniculitis
- Squamous cell carcinoma – Associated with keratotic plaques.
- Venous or arterial ulcerations
- Granulomatosis with polyangiitis
- Traumatic ulceration
- Necrobiosis lipoidica – Usually associated with atrophic plaques.
- Tertiary syphilis
- If a patient has traveled to tropical countries within the last 6 months, diagnoses such as leishmaniasis (Old World and New World), tropical ulcer, and Buruli ulcer must be considered.
- Because PG may be a relapsing and remitting condition with treatment, atrophic, hyperpigmented, and hypopigmented scarring may occur. These scars may resemble scars from leukocytoclastic vasculitis or atrophie blanche.
- Insect or spider bite
- Mycobacterium marinum infection
- Sweet's syndrome