Pyoderma

Background

• 1/100,000 people per year in US, primarily 40s-50s year of age
• Dysfunction of activated neutrophils
• >50% associated with systemic disease:
  • IBD
  • Polyarthritis, sero-negative and -positive
  • Leukemia
  • Less commonly psoriatic arthritis, OA, RA, spondyloarthopathy, hepatitis, PBC, myelomas, SLE, Sjogren

Clinical Features

• Extracutaneous manifestations (due to sterile neutrophilic infiltrates)
  • Culture-negative pulmonary infiltrates most common
  • CV, CNS, GI, eyes, liver, spleen, bones, LNs
• Features
  • Initial lesion - bite-like, small, red papule or pustule (many patients attribute spider bite)
  • Changes into larger, ulcerative lesion
  • Two primary variants:
    • Classic ulcerative form - usually on legs, deep ulceration, violaceous border along ulcer bed
    • Superficial, atypical form - hands/forearms/face, vesiculopustular
  • Less common variants: 1) Peristomal pyoderma, 2) Genital pyoderma (must differentiate from STI), 3) Pyostomatitis vegetans (intraoral)

Differential Diagnosis

• Pyoderma is Dx of exclusion
• Systemic diseases
  • Neutrophilic dermatoses (Sweet, Behcet, etc.)
  • Calciphylaxis - very important to differentiate due to treatment
  • Arterial/venous insufficiency
  • Blastomycosis
  • Hidradenitis suppurative
  • TB gumma, mycobacterial infections
  • Malignancy (squamous cell)
  • Vasculitis
  • Ecthyma gangrenosum (pseudomonas)

Travel-related skin conditions

• Papules
  • Insect bites
  • Scabies
  • Seabather's eruption
  • Cercarial dermatitis (Swimmer's Itch)
• Macular
  • Chikungunya
• Sub Q Swelling and Nodules
  • Myiasis
  • Tungiasis
  • Loa loa
  • African Trypanosomiasis
  • Onchocerciasis
• Ulcers
  • Tropical pyoderma
  • Leishmaniasis
  • Mycobacterium marinum
  • Buruli ulcer
  • Dracunculiasis (Guinea Worm disease)
• Linear and Migratory Lesions
  • Cutaneous larvae migrans
  • Photodermatitis

See also domestic U.S. ectoparasites

Evaluation

• No specific criteria
• Labs
  • CBC, CMP, UA, hepatitis profile
  • Tissue cultures (comprehensive, all organisms)
  • VDRL
  • ANCA
  • Coags
  • Anti-phospholipid AB
  • Referral for heme malignancy workup
  • Referral for IBD workup
• Imaging - CXR if systemic disease suspected

Management

• Nonsurgical management
  • Necrotic tissue should be gently removed
  • Wide surgical debridement results in enlargement of ulcer
• Medical management
  • Small ulcers - steroid cream/injections, silvadene compression dressings, PO antibiotics like dapsone or minocycline
  • Severe - steroids, immunologic treatment, biologics, IVIG, plasmapheresis

Disposition

• Dermatology referral, consider surgical if suspecting other necrotizing diseases requiring debridement

See Also

• Travel Medicine