Pityriasis Versicolor Flashcards
Define pityriasis versicolor
A common fungal infection of the skin that is localized to the outermost layer of the epidermis (the stratum corneum).
also known as tinea versicolor
Aetiology of pityriasis versicolor
Malassezia yeasts (globosa, sympodialsis, furfur)
- Part of the normal skin flora in 90% adults
- Colonisation in sebaceous gland-rich areas e.g. upper trunk, flexures, scalp
- Infection due to switch from saprophytic to mycelial form
Risk factors for pityriasis versicolor
Warm, humid environment
Hyperhidrosis
Occlusive dressings, clothing, ointment, creams
Malnutrition
Immunodeficiency/suppression (DM, Cushing’s, steroids)
Symptoms and signs of pityriasis versicolor
Rash
- Discreet/confluent macules or patches
- Insidious onset
- fawn, pink, red, brown, white colour
- Upper trunk, upper arms, neck, abdomen
- May be itchy
- Fine powdery scale
Differentials for pityriasis versicolor
Vitiligo
Psoriasis
Tinea corporis
Seborrheic dermatitis
Lyme disease
Pityriasis rosea
Erythrasma
Secondary syphilis
Management for pityriasis versicolor
Clinical diagnosis
Advice:
- Not contagious as the yeast is normally present on human skin
- Infection is not due to poor hygiene
- Treatment is highly effective but may need to be repeated as recurrence is common
- Discolouration may take several weeks or months to fully resolve
Extensive involvement: Ketoconazole 2% shampoo / selenium sulphide 2.5% shampoo
- Apply once daily for up to 5 days / 7 days
- Use once every 2-4 weeks after for up to 6 months to prevent recurrence
- Selenium CI in pregnancy
Small area involved: clotrimazole, econazole, ketoconazole
- BD for 2-3 weeks
Prognosis for pityriasis versicolor
Chronic infection
Spontaneous remission without treatment is unusual
Prognosis very good with treatment
Skin pigmentation changes fully resolve within 2-3 months of treatment
Recurrence is common - 60% of people in the first year and 80% after 2 years
