Pyoderma

Uncommon neutrophilic dermatosis

Epidemiology

• Rare at 1 in 100,000

• Most common in young to middle-aged adults aged 40 to 60

• Female > male

Pathogenesis

• Immune dysregulation with lots of interleukin and TNF alpha

• Pro-inflammatory state

• Genetic susceptibility

Clinical

Initial inflammatory papule, pustule, vesicle or nodule that expands and breaks down to erosion or ulcer

Types

• Ulcerative

• Bullous

• Pustular

• Vegetative

Special

• Peristomal

• Genital

• Extracutaneous e.g. lungs, cornea, liver

• Post-operative occurring 2 weeks after surgery

Associated

• 40% have IBD

• 20% have inflammatory arthritis

• 5% solid organ cancers

• 5% blood cancers

• 5% blood disorders e.g. MGUS, MDS, PCV

Diagnosis

Major criterion:

• Biopsy of ulcer edge demonstrating a neutrophilic infiltrate

Minor criteria:

• Exclusion of infection

• Pathergy

• Personal history of inflammatory bowel disease or inflammatory arthritis

• History of papule, pustule, or vesicle that rapidly ulcerated

• Peripheral erythema, undermining border, and tenderness at the site of ulceration

• Multiple ulcerations (at least one occurring on an anterior lower leg)

• Cribriform or "wrinkled paper" scar(s) at sites of healed ulcers

• Decrease in ulcer size within one month of initiating immunosuppressive medications

Biopsy often non-specific but rules out other conditions

FBC, UEC, LFT, Glucose, ANA, ANCA, Coags, Hepatitis, RH Factor, SPEP, CXR, Scopes

Differential

Vascular occlusion disorders, venous disease, vasculitis, malignancy, cutaneous infection, drugs, exogenous tissue injury, and ulcerative inflammatory disorders (eg, cutaneous Crohn’s disease and ulcerative necrobiosis lipoidica) may be mistaken for PG

Treatment

Wound management

• Local care - Saline cleanse, mild antispetic, dressings that promote a moist environment, non adherent

• Pathergy - Avoid unnecessary traumatic insults (e.g. use of wet to dry dressings, caustic substances e.g. silver nitrate)

• Surrounding skin - use of zinc oxide paste or petrolatum may help prevent wound breaksdown at the edge

• Hyperbaric oxygen have been reported to heal some patients

• Surgery - risk of pathergy, only in select cases

• Limited disease - potent local steroids, tacrolimus may help

• Extensive disease - Systemic glucocorticoids, study shows 50% complete healing at 6 months on Prednisolone or Cyclosporine

• Second line - Infliximab, other biologics, IVIG

• Pain management

Prognosis

• More than 50% achieve complete wound healing within 12 months

Reference

• Pyoderma Gangrenosum Treatment - UpToDate

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