Pityriasis Versicolor

Pityriasis versicolor is a common, benign superficial fungal infection caused by the overgrowth of Malassezia yeast, which is a normal inhabitant of healthy skin.

• Discoloration: Patients report "spots" or patches that are lighter (hypopigmented), darker (hyperpigmented), or occasionally pink/red (erythematous) compared to their normal skin tone.

• Timeline: Symptoms often intensify during the summer or after travel to warm, humid climates. It is frequently noticed after sun exposure because the yeast produces a chemical that prevents the underlying skin from tanning.

• Symptoms: Usually asymptomatic, but patients may mention mild itching (pruritus), especially when they become hot or sweaty.

• Course: It is a chronic, relapsing condition. Patients often mention that the patches disappear in winter and return every summer.

Diagnosis is clinical, characterized by the "versicolor" (varied color) nature of the lesions.

• Morphology: Small, well-demarcated, round or oval macules and patches.

• Scale: A very fine, "bran-like" scale (pityriasis) is often present. If not visible, it can be elicited by gently stretching or scraping the skin (the "evoked scale" sign).

• Distribution: Primarily affects the "seborrheic" areas where oil glands are most active: the upper trunk (back and chest), shoulders, and neck. It rarely extends below the waist.

• Coalescence: Small spots often merge together to form large, map-like geographic patterns.

Crucial Note for Darker Skin Tones

• High Contrast: In darker skin, the hypopigmented (pale) variant is most common and creates a striking contrast, which can be very distressing for the patient.

• Differential Diagnosis: * Vitiligo: Unlike Pityriasis Versicolor, vitiligo patches are "chalk-white" (depigmented), have no scale, and typically appear around the eyes, mouth, or knuckles.

  • Pityriasis Alba: Common in children with eczema; these patches are less well-defined, have a "powdery" scale, and usually appear on the face.

  • Pityriasis Rosea: Usually follows a "herald patch" and a Christmas-tree distribution; the scales are "collarette" (attached at the edges).

• Wood’s Lamp: Under ultraviolet light, the patches may emit a faint yellow or orange-gold fluorescence, though this is not as bright as the red in Erythrasma.

Topical Treatments: First-line treatments include antifungal agents such as selenium sulfide 2.5% lotion, ketoconazole 2% shampoo, or clotrimazole 1% cream, applied daily for 1-2 weeks. Patients should be advised to leave these on for about 10-15 minutes before rinsing to maximize efficacy.

Oral Treatments: In cases of widespread infection or frequent recurrence, oral antifungals like fluconazole or itraconazole may be used. Fluconazole 300 mg as a single dose or itraconazole 200 mg daily for 5-7 days can be effective.

Preventive Maintenance: Monthly topical antifungal application (e.g., selenium sulfide) can prevent recurrences in susceptible individuals. Emphasizing hygiene, drying the skin properly, and avoiding excessive heat can reduce recurrence risk.

Darker Skin Tones – Specific Treatment Risks:

• Managing Expectations: This is the most critical step. Patients must understand that the medication kills the yeast, but does not fix the color immediately. The pale spots are "tanning shadows." The skin color will only even out once the patient is exposed to the sun again and the melanocytes recover, which can take 3–6 months.

• Post-Inflammatory Hyperpigmentation: If the versicolor was the "dark" (hyperpigmented) type, those spots may also take several months to fade back to the baseline skin tone.

• DermNet NZ – Pityriasis Versicolor: https://dermnetnz.org/topics/pityriasis-versicolor

• StatPearls – Tinea Versicolor (2024 update): https://www.ncbi.nlm.nih.gov/books/NBK482500/

• American Academy of Dermatology – Tinea Versicolor Diagnosis and Treatment: https://www.aad.org/public/diseases/a-z/tinea-versicolor-treatment