Cutaneous Fungal Infection

Aka: Cutaneous Fungal Infection, Fungal Skin Infection, Superficial Fungal Infection, Tinea Infection, Tinea, Dermatophytosis, Dermatomycoses, Dermatophyte Infection

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II. Definitions

  1. Tinea (Ringworm)
    1. Superficial Fungal Infections caused by dermatophyte molds
  2. Dermatophytes
    1. Fungal organisms that cause Tinea
    2. Dermatophytes inhabit keratinized tissues (hair, skin and nails)
      1. Dermatophytes are able to digest keratin via keratinase secretion
    3. Includes three genera: Trichophyton, Microsporum, Epidermophyton
      1. Overall, >30 dermatophyte species that infect humans

III. Causes: Tinea

  1. Children
    1. Tinea Capitis (scalp infection)
    2. Tinea Corporis (Ringworm)
    3. Tinea Faciale (facial infection)
  2. Adolescents and adults
    1. Tinea Manum (Hand Infection)
    2. Tinea Pedis (Athlete's Foot)
    3. Tinea Unguium (Onychomycosis, ToenailFungus)
    4. Pityriasis Versicolor or as previoulsy known, Tinea Versicolor (uneven tanning on the trunk )
  3. Adolescent and adult males
    1. Tinea Barbae (beard-area Superficial Folliculitis)
    2. Tinea Cruris (Jock Itch)
    3. Tinea Corporis Gladiatorum

IV. Causes: Other Cutaneous Fungal Infections

  1. Cutaneous Candidiasis (yeast)
    1. Intertrigo
    2. Chronic Paronychia
  2. Cutaneous Blastomycosis
  3. Sporotrichosis

V. Causes: Emerging and Resistant Dermatophytes

  1. Trichophyton indotineae (Trichophyton mentagrophytes Genotype VIII)
    1. Resistant and recurrent Dermatophyte Infections in immunocompetent patients
    2. Transmission via direct contact and via fomites
    3. More common in South Asia (uncommon in U.S. outside of travel exposure)
    4. Resistant to Terbinafine (treat with oral Itraconazole for 3 months)
  2. Trichophyton mentagrophytes Genotype VII
    1. Pruritic annular Scaling lesions on face, genitalia/groin and trunk
    2. Most commonly transmitted via Men who have Sex with Men
    3. Originally described in southeast asia and france, and in U.S. as of 2024
    4. Responds to oral Terbinafine for 3 months
  3. Terbinafine Resistant Trichophyton rubrum
    1. Described with Tinea Corporis in southern U.S., and Onychomycosis in U.S. and Canada
    2. Treat with oral Itraconazole or Posaconazole

VI. Management: Pearls

  1. Limit Nystatin use to Cutaneous Candidiasis (not effective against Tinea Infections)
  2. Butenafine (Lotrimin) and Terbinafine (Lamasil) are preferred topical agents for tinea
  3. Avoid oral Ketoconazole due to hepatotoxicity
  4. Avoid combination agents containing Antifungals with high-potency Corticosteroids
    1. Dilutes the Antifungal concentration and may exacerbate the Fungal Infection
    2. High potency Corticosteroids may cause local skin adverse effects (e.g. skin atrophy)
    3. Greater risk of developing Antifungal resistance

VII. References

  1. Caplan (2025) Am Fam Physician 112(4): 382-92 [PubMed]
  2. Ely (2014) Am Fam Physician 90(10): 702-10 [PubMed]

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