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Tinea versicolor (Pityriasis versicolor)

Etiology: - Malassezia furfur Epidemiology: 1) common disorders 2) occurs most frequently in adolecents or young adults Pathology: 1) growth of Malassezia furfur in the stratum corneum 2) in yeast form, generally does NOT cause disease 3) lesions associated with conversion to hyphal form 4) heat & humidity promote infection 5) Malassezia furfur is lipophilic & produces C9 & C11 dicarboxylic acids (inhibiting tyrosinase in vitro) 6) associated with sebum production of skin Clinical manifestations: 1) eruption of white, tan, brown or red patches - may be described as salmon-colored oval patches - hypopigmentation more common in persons of color [2] - multiple thin oval, hyperpigmented or hypopigmented scaly papules & plaques 2) lesions generally occur on the sternal skin, back, lateral chest, sides of neck 3) facial lesions can occur on infants & children 4) macules have fine white scale when scratched - lesions may not itch [2] 5) minimal inflammation occurs 6) may appear hypopigmented with suntanning [2] * images [8,9,10] Laboratory: 1) see Tinea 2) KOH skin preparation: - short hyphae & round spores resembling yeast (spaghetti & meatballs) 3) Wood's lamp -> golden fluorescence Differential diagnosis: - pityriasis rosea - herald patche - papulosquamous eruption that occurs in the skin tension lines (Langer lines) - appears on the trunk in a 'Christmas tree' pattern [11] Management: 1) several weeks of treatment or longer before skin color returns to normal [4] 2) selenium sulfide 2.5% - lather on for 5 minutes, then rinse 3) topical imidazole compound is first line [2] a) clotrimazole (Lotrimin) b) miconazole (Monistat) c) ketoconazole (Nizoral) d) econazole (Spectazole) e) sulconazole (Exelderm) f) oxiconazole (Oxistat) g) terconazole (Terazol) 4) systemic antifungal for recalcitrant Tinea versicolor [2] a) itraconazole 200 mg/day for 7 days or 100 mg/day for 14 days b) fluconazole 300 mg/week for 2-4 weeks c) ketoconazole 400 mg PO single dose [5] not effective [2] - repeat 400 mg dose in 1 week - not recommended [7] d) fluconazole 400 mg PO single dose e) monthly itraconazole 400 mg to prevent recurrence [4]

Related

Malassezia furfur (Pityrosporum obiculare) stratum corneum (keratin {horny} layer)

Useful

antifungal agent selenium sulfide (Selsun, selenium disulfide)

General

Tinea

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996
  2. Medical Knowledge Self Assessment Program (MKSAP) 14, 16, 17, 18. American College of Physicians, Philadelphia 2006, 2012, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 277, 296
  4. Prescriber's Letter 9(3):15 2002
  5. Prescriber's Letter 11(2):11 2004 Detail-Document#: 200208 (subscription needed) http://www.prescribersletter.com
  6. Hu SW, Bigby M. Pityriasis versicolor: a systematic review of interventions. Arch Dermatol. 2010 Oct;146(10):1132-40 PMID: 20956647
  7. Prescriber's Letter 21(7): 2014 Treatment of Tinea Versicolor Infections. Detail-Document#: 300707 (subscription needed) http://www.prescribersletter.com
  8. Tinea versicolor (image) American Academy of Dermatology https://www.aad.org/public/diseases/color-problems/tinea-versicolor
  9. Burkhart CG, Elston DM (image) Medscape: Tinea Versicolor http://emedicine.medscape.com/article/1091575-overview
  10. DermNet NZ. Pityriasis versicolor (images) http://www.dermnetnz.org/fungal/pityriasis-versicolor.html
  11. NEJM Knowledge+ Dermatology