Tinea versicolor, also known as pityriasis versicolor, is a superficial fungal infection of the skin that is often confused with other common rashes.
Cause of Tinea Versicolor
The yeasts, Pityrosporum orbiculare and Pityrosporum ovale, are a part of the normal skin flora. They reside in the stratum corneum and hair follicles and have an affinity for oil glands. Certain factors can cause these yeasts can convert to a pathogenic form known as Malassezia furfur, which causes the rash of tinea versicolor. Some of these predisposing factors include:
- Removal of the adrenal gland
- Cushing's disease
- Pregnancy
- Malnutrition
- Burns
- Steroid therapy
- Suppressed immune system
- Oral contraceptives
- Excess heat
- Excess humidity
Who Gets Tinea Versicolor
Tinea versicolor can occur at any age, but is most common in adolescence and early adulthood, a time when the sebaceous glands are more active. It is also more common in tropical and semi-tropical climates. Tinea versicolor has a recurrence rate of 80% after 2 years.
Appearance of Tinea Versicolor
The rash of tinea versicolor is a hypopigmented, hyperpigmented, or red flat eruption that may coalesce into large patches with an adherent fine scale. This rash occurs mainly on the trunk, but can also occur on the extremities. Hypopigmentation occurs because the yeast produces a chemical that turns off the melanocytes, resulting in decreased melanin production. The hyperpigmentation or redness occur as a result of the inflammatory response in the skin.
Pictures of Tinea Versicolor
The following pictures show the tinea versicolor rash in various locations:
- Tinea Versicolor - close-up
- Tinea Versicolor - close-up
- Tinea Versicolor - shoulders
- Tinea versicolor - back
- Tinea versicolor - back
Diagnosis of Tinea Versicolor
Tinea versicolor can be diagnosed by three different tests:
- A KOH test shows a characteristic "spaghetti and meatballs" appearance under the microscope.
- Under a Wood's light examination, the yeast fluoresces pale yellow.
- A fungal culture can be performed after adding oil to the culture medium, but it is rarely necessary.
Rashes that Look Like Tinea Versicolor
The following rashes can be confused with tinea versicolor:
- Vitiligo
- Pityriasis alba
- Seborrheic Dermatitis
- Syphilis
- Pityriasis Rosea
- Nummular eczema
- Guttate psoriasis
Treatment of Tinea Versicolor
There are a number of different medications used to treat tinea versicolor. Because the yeast inhabits the top layer of the skin, topical antifungal medications are very effective. If the rash is extensive, oral antifungal medications may be needed. It is important to note that even though the pathogenic yeast has been eradicated after treatment, the hypopigmentation may persist for weeks until the melanocytes start to produce melanin again. Because this rash has a high recurrence rate, medication may be needed periodically to prevent recurrence.
