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A. Introduction [3]

  1. Rare dermatologic condition
    1. Frequently associated with systemic disease
    2. Most common association is with inflammatory bowel disease (IBD)
    3. >95% of patients are >15 years old
  2. No pathognomonic clinical, laboratory, gross, or histopathological findings
  3. Ulcerating lesions often beginning at sites of trauma
  4. Initial lesion is often a pustule and is frequently accompanied by pain

B. Description of Lesions [4]

  1. Lesions most commonly on legs, but may be anywhere
  2. Classically begins as a pustule which becomes nodular and ulcerates
    1. Central ulceration with necrotic tissue, blood, exudate
    2. Periphery of ulcer is usually violaceous
  3. Inflammation spreads through the dermis, leaving epidermis detached
  4. Border is "undermined" with free epidermis
  5. Size is 1-30cm
  6. Variant Types of Pyoderma
    1. Pustular eruption of ulcerative colitis - 1-3mm lesions on erythematous base
    2. Pyostomatitis vegetans - pustular vegetatitve process involving oral mucus membranes
    3. Bullous pyoderma - occurs with pre- and true-leukemic conditions; more superficial
    4. Malignant pyoderma - usually on head, neck; strongly associated with ANCA vasculitis [5]
    5. Peristomal pyoderma - usually in patients with inflammatory bowel disease [4]
  7. Differential Diagnosis
    1. Misdiagnosis is common and leads to prolonged inappropriate treatment [6]
    2. Eccthymic gangrenosum - associated with pseudomonas infection
    3. Sweet's Syndrome - acute neutrophilic dermatosis
    4. Paraneoplastic Syndromes
    5. Vasculitis
    6. Vascular Insufficiency (Venous Ulcers)
  8. Thorough evaluation for associated diseases and differential diagnoses is essential [6]

C. Associated Disease

  1. IBD
    1. Ulcerative Colitis >70% of cases
    2. Crohn's Disease (less common) [2]
  2. Arthritis
    1. Seronegative ± IBD (spondylitis present in many cases)
    2. Rheumatoid Arthritis
  3. Hematologic Disease
    1. Myelocytic Leukemia
    2. Hairy Cell Leukemia
    3. Myelofibrosis
    4. IgA Gammopathy
  4. Vasculitis
    1. Malignant pyoderma may coexist with ANCA disease [5]
    2. Most commonly with Wegener's Granulomatosis
  5. Rare Associations
    1. Autoimmune Liver Disease: Primary Biliary Cirrhosis, Autoimmune Hepatitis
    2. Systemic Lupus Erythematosus
    3. Thyroid Disease
    4. Sarcoidosis, other pulmonary disease

D. Histology [1]

  1. Depends on portion of lesion from which biopsy is taken
  2. Central neutrophilic infiltration with absence of leukocytoclasts
  3. Lymphocytic vasculitis is not always present [2] but helps to confirm diagnosis
  4. Peripheral zone has lymphocytic infiltration, endothelial swelling, fibrinoid necrosis
  5. Presence of immunoglobulin (Ig) and/or complement varies
  6. Skin biopsy from advancing edge for evaluation of vasculitic changes

E. Treatment [2,7]

  1. Total colectomy will usually (not always) lead to regression of PG in ulcerative colitis
  2. Glucocorticoids
    1. Intralesional, topical, and systemic glucocorticoids may be helpful
    2. Prednisone at 40-120mg/day is very effective in nearly all patients
    3. Pulse methylprednisolone at 1gm/d x 5 days (then give oral steroid) is also effective
    4. Oral prednisone given on alternate days may be used as maintenance
    5. Azathioprine may be used as a glucocorticoid-sparing agent [2]
  3. Dapsone
    1. May be used as adjunctive therapy, and for steroid-sparing activities
    2. Dose is 100-200mg/day
    3. Caution with this agent (methemoglobinemia); G6PD deficiency
  4. Other Agents [7]
    1. Intravenous Immunoglobulin (IVIg)
    2. Cyclosporine 3-5mg/kg po qd [8]
    3. Clofazamine (200mg/d)
    4. Mycophenolate mofetil 1gm po bid
    5. Combination therapy

References

  1. Callen JP. 1998. Lancet. 351(9102):581 abstract
  2. Haynes HA, Grame-Cook FM, Lerner LH. 2001. NEJM. 344(19):1461 (Case Record)
  3. Lionetti P, Battini ML, Resti M, Falcini F. 1998. Lancet. 351(9098):262 (Case Report) abstract
  4. Hughes AP, Jackson JM, Callen JP. 2000. JAMA. 284(12):1546 abstract
  5. Gibson LE, Daoud MS, Muller SA, Perry HO. 1997. Mayo Clin Proc. 72(8):734 abstract
  6. Weenig RH, Davis MDP, Dahl PR, Su WPD. 2002. NEJM. 347(18):1412 abstract
  7. Hohenleutner U, Mohr VD, Michel S, Landthaler M. 1997. Lancet. 350(9093):1748 abstract
  8. Elgart G, Stover P, Larson K, et al. 1991. J Am Acad Dermatol. 24:83 abstract
  9. Powell FC, Schroeter AL, et al. 1985. Quart J Med. 55:173 abstract