Cutaneous Fungal Infections (Dermatophytosis)
Fungal infections, primarily caused by dermatophytes (*Trichophyton*, *Microsporum*, *Epidermophyton*), are classified by the anatomical site of infection.
Common Clinical Presentations
| Infection Type | Key Features |
|---|---|
| Tinea Corporis | “Ringworm”; annular plaques with central clearing and active, scaly borders. |
| Tinea Capitis | Scalp scaling; “black dot” alopecia; can lead to a Kerion (inflammatory boggy mass). |
| Tinea Pedis | “Athlete’s foot”; interdigital maceration or moccasin-type scaling. |
| Tinea Versicolor | Hypo- or hyper-pigmented macules; *Malassezia* yeast; “spaghetti and meatballs” on KOH. |
Diagnostic & Treatment Pearls
- KOH Preparation: The gold standard for office diagnosis. Look for branching septate hyphae.
- Treatment:
- Most localized tinea respond well to topical antifungals (e.g., Clotrimazole, Terbinafine).
- Systemic therapy (Oral Terbinafine or Itraconazole) is required for Tinea Capitis and extensive Tinea Corporis.
- Resources: For high-yield clinical questions and free courses, visit mymedschool.org.
High-Yield Exam Pearl:
- Steroid Caution: Never use topical steroids for undiagnosed scaly rashes; they can cause “Tinea Incognito,” masking the classic features and facilitating deeper fungal growth.
- Tinea Capitis: Always treat systemically; topical agents cannot penetrate the hair follicle adequately.