II. Etiology

  1. Not a true dermatophyte (tinea) infections
  2. Caused by yeasts (genus Malassezia)
    1. Pityrosporum orbiculare
    2. Pityrosporum ovale
    3. Malassezia furfur (prior name for organisms above)

III. Signs

  1. Characteristics
    1. Macules with fine scale
    2. Hyperpigmented or hypopigmented Macules (or pink Plaques)
  2. Distribution
    1. Neck
    2. Trunk (chest and back)
    3. Proximal extremities

IV. Diagnosis

  1. Potassium Hydroxide (KOH)
    1. Scrape fine powdery scale with #15 blade
    2. Spaghetti (hyphae) and meatball (yeast) appearance
  2. Wood's Lamp (variably present)
    1. Irregular pale yellow fluorescence
    2. Fluorescence disappears with resolution

V. Differential Diagnosis

VI. Management

  1. Hypopigmentation resolves slowly after treatment
  2. Recurrent infections (recurrence rate is high)
    1. Consider repeat treatment prior to summer
    2. Frequently worn clothing may harbor fungus
      1. Consider discarding suspected clothing
      2. Consider boiling suspected clothing
  3. First Line: Topical Antifungal
    1. OTC versus prescription agents
      1. Both Selenium sulfide 1% (Selsun Blue) and Ketoconazole 1% (Nizoral A-D) are available OTC
      2. Best studied efficacy is with the higher concentration prescription items
        1. Efficacy of lower concentrations is unknown
    2. Selenium sulfide (Selsun, Exsel) 2.5% lotion
      1. Apply lather neck to knees
      2. Course
        1. Apply once daily for 7 days
        2. Wash off after 5-10 minutes
      3. Alternative regimen 1
        1. Apply three to five times per week for 2-4 weeks
        2. Wash off after 5-10 minutes
      4. Alternative regimen 2
        1. Apply once weekly for 4 weeks
        2. Wash off after 24 hours
    3. Zinc pyrithione
    4. Ketoconazole 2% cream
      1. Apply once daily for 14 days
    5. Terbinafine (Lamasil) topically
      1. May result in longer, sustained resolution
  4. Second line: Systemic Antifungal
    1. General
      1. Exercise to sweating after each dose
        1. May help distribute more medication to skin
      2. Avoid bathing for 12 hours after application
      3. Avoid oral Terbinafine due to low efficacy (possibly due to low skin concentrations)
    2. Fluconazole (preferred)
      1. 400 mg orally for one single dose OR
      2. 300 mg orally now and again in 2 weeks
    3. Itraconazole
      1. 400 mg orally daily for 3-7 days OR
      2. 200 mg twice daily for one day per month (to prevent recurrence)
    4. Ketoconazole
      1. Avoid due to hepatotoxicity risk (requires baseline and weekly Liver Function Test monitoring)
      2. Preveiously used at 400 mg orally for one single dose or 200 mg PO qd for 7 days

VII. References

  1. (2014) Presc Lett 21(7): 41
  2. Habif (1996) Clinical Dermatology, Mosby, p. 402-5
  3. Gilbert (2013) Sanford Antibiotic Guide
  4. Plensdorf (2017) Am Fam Physician 96(12): 797-804 [PubMed]
  5. Savin (1996) J Fam Pract 43(2):127-32 [PubMed]
  6. Zuber (2001) Postgrad Med 109(1):117-32 [PubMed]

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