Diagnosis

Pityriasis versicolor

Etiology

Cause [a83]

• Malassezia furfur, formerly known as Pityrosporum

• Causes infection in some individuals while remains as normal flora in others

• Genetic predisposition and a hereditary component may play a role

Pathophysiology [a83]

1. Malassezia is a fungal inhabitant of the normal skin flora present on healthy skin (oily regions: face, scalp, and back)

2. Not contagious

3. Unknown host trigger --> Malassezia transforms into its pathogenic filamentous form --> can cause tinea versicolor

Risk factors [a83]

• Oily skin: Poor hygiene, humidity, hyperhidrosis (heavy sweating), oily lotions

• Immunosuppression: Steroid therapy, Cushing disease, Diabetes

• Antibiotic therapy

• Malnutrition

Epidemiology

Incidence per 100.000 [a83][arn][vpi][ef7][dys]

Approach

• Rash:

  • Type: hyperpigmented or hypopigmented, finely scaling patches or plaques

  • Pattern: face (children), scalp, trunk, neck, and proximal extremities

• Dermoscopy

• Wood's lamp

• Microscopy with KOH

• Biopsy

Treatment

1. Topical treatment: [a83][arn]

   • Ketoconazole 2% shampoo for 3 days

   • Selenium sulfide 2.5% shampoo or lotion applied for 10 minutes daily for 1 week

   • Terbinafine 1% once or twice daily from 1 to 4 weeks

   • Ciclopirox 1% applied twice daily for 2 weeks

   • Zinc pyrithione 1% daily for 5 minutes for 2 weeks

   • Ultraviolet UV-B phototherapy (limited evidence)

2. Oral therapy: if resistant to topical treatment or with widespread disease

   • Itraconazole 200 mg daily for 7 days

   • Fluconazole 300 mg weekly for 2 weeks

3. Prophylaxis:

   • Topical selenium sulfide 2.5% or ketoconazole 2% shampoo applied to the entire body for ten minutes once per month

   • Oral Itraconazole 200 mg twice daily, once each month

Differential diagnoses

Candidiasis, Eczema, Erythrasma, Folliculitis, Mycosis fungoides, Pityriasis alba, Pityriasis rosea, Psoriasis, Seborrheic dermatitis, Syphilis, Tinea, Tinea corporis, Vitiligo