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Superficial Mycoses: Dermatophytes and Candida Infections

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Superficial Mycoses

Superficial mycoses are primarily caused by two groups of fungi:

  • Dermatophytes
  • Candida species

Dermatophyte Infections (Ringworm)

Dermatophytes are keratinophilic fungi that thrive in the stratum corneum. They are classified into three main genera:

  • Trichophyton: Affects skin, hair, and nails.
  • Epidermophyton: Affects skin and nails.
  • Microsporum: Affects skin and hair.

Reservoirs:

  • Zoophilic: Transmitted from animals.
  • Geophilic: Found in soil.
  • Anthropophilic: Transmitted from humans.

Clinical Classification of Tinea

  1. Tinea Capitis: Scalp infection.
  2. Tinea Corporis: Trunk infection.
  3. Tinea Cruris/Intertriginous: Folds infection.
  4. Tinea Pedis/Manuum: Feet and hands infection.

1. Tinea Capitis

  • Tonsurans: Microsporic, Trichophytic, or Kerion (alopecia).
  • Favus: Caused by Trichophyton schoenleinii (can lead to permanent alopecia).

2. Tinea Corporis (Hairless Skin)

  • Kerion: Inflammatory nodular lesion.
  • Herpes Circinatus: Rounded oval lesion with active, vesicular edges and an involuting center.
  • Tinea Plaque: Enlarged lesions formed by coalescing plaques.
  • Tinea Ringworm: Common in children, presenting as red rings.
  • Concentric Tinea: Multiple rings within a single lesion.
  • Majocchi's Granuloma: Deep nodular dermatophytic infection on limbs.
  • Pityriasis Versicolor: Superficial fungal infection.
    • Achromiant: Hypopigmented rounded patches.
    • Erythematous: Pink, erythematous patches often seen in lighter skin tones.

3. Tinea of the Folds

  • Large Folds: Inguinal and axillary regions.
  • Small Folds: Interdigital spaces, often exacerbated by poor hygiene or diabetes, presenting as macerated, whitish, or pinkish skin.

4. Tinea of Hands and Feet

  • Foot Infections:
    • Hyperkeratotic: Dominated by scaling.
    • Dyshidrotic: Dominated by vesicles.
    • Intertriginous: Located in interdigital spaces.
  • Nail Infections (Onychomycosis):
    • Dermatophytes: Distal nail involvement, loss of shine, and nail thickening.
    • Candida albicans: Proximal nail involvement, often presenting with a red periungual rim.

Candida Albicans Infections

Candida albicans are saprophytic yeasts that become pathogenic when the local pH is altered or the host is immunocompromised (e.g., AIDS, oral candidiasis). They frequently affect skin folds, similar to dermatophytes, including axillary, submammary, and inguinal regions.

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