Skin and soft tissue infections in the returned traveller

Differential Diagnosis

Papular Lesions

• Insect bites, including bed bugs and fleas: often grouped papules
  • Flea bites may have hemorrhagic centres
  • Scabies presents as pruritic papular rash, possibly with papules or pustules in a linear pattern, especially in the webbed spaces of the fingers
• Onchocerciasis: sub-Saharan Africa (rarely Latin America), presenting as generalized pruritic papular dermatitis.

Nodular or Subcutanous Lesions

• Bacterial skin infections
  • Cellulitis, but must consider drug-resistant Staphylococcus aureus
  • Pyoderma, impetigo, abscesses, erysipelas, lymphangitis, and ulcerations
  • Secondary to insect bites or trauma
• Myiasis (Cordylobia anthropophaga in Africa, Dermatobia hominis in Americas)
• Tungiasis: caused by the sand flea (Tunga penetrants)
• Loa loa filariasis: sub-Saharan African with migratory, transient, painful or pruritic swelling. Rarely, crosses the conjunctiva. Eosinophilia is common.
• Gnathostomiasis: Southeast Asia, Africa, and the Americas, from eating undercooked freshwater fish. Causes migratory subcutaneous nodules that are painful or pruritic. Can occur weeks to years after exposure. Eosinophilia is common.

Macular Lesions

• Tinea versicolor (Malassezia furfur)
• Tinea corporis, or ringworm
• Lyme disease (Borrelia burgdorferi): in North America, Europe, and Russia
• Leprosy

Linear Lesions

• Cutaneous larva migrans (Ancylostoma spp.)
• Larva currens (Strongyloides stercoralis): similar to CLM but moves faster ("running")
• Lymphocutaneous spread, as in sporotrichosis, Mycobacterium marinum, leishmaniasis, bartonellosis, Nocardia, tularemia, melioidosis, and blastomycosis
• Phytophotodermatitis: non-infectious reaction between lime juice and sunlight exposure, essentially an exaggerated sunburn in the distribution of the spilled juice. Resolves over weeks to months.