Pharmacy and Medicine

Tinea versicolor, also known as pityriasis versicolor, is a superficial fungal infection of the skin that is often confused with other common rashes.

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

Removal of the adrenal gland

Cushing's disease

Pregnancy

Malnutrition

Burns

Steroid therapy

Suppressed immune system

Oral contraceptives

Excess heat

Excess humidity

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.

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.

Tinea versicolor can be diagnosed by three different tests:

1.A KOH test shows a characteristic "spaghetti and meatballs" appearance under the microscope.

2.Under a Wood's light examination, the yeast fluoresces pale yellow.

3.A fungal culture can be performed after adding oil to the culture medium, but it is rarely necessary.

Rashes that Look Like Tinea Versicolor

Vitiligo

Pityriasis alba

Seborrheic Dermatitis

Syphilis

Pityriasis Rosea

Nummular eczema

Guttate psoriasis

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.

Tinea versicolor is a rash that occurs after the normal skin yeasts, Pityrosporum orbiculare or Pityrosporum ovale, transform to a pathogenic form and turn off melanin-producing cells in the skin. 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. Because tinea versicolor has a recurrence rate of 80% after 2 years, periodic use of medications may be needed to suppress the rash.

Topical antifungal medications are the treatment of choice for tinea versicolor. The following topical antifungal treatment regimens have been shown to produce a greater than 70% clinical response rate:

2% Ketoconazole cream applied once daily for 11-22 days

2% Ketoconazole shampoo regimen (lathered over affected and surrounding areas and left on for at least 5 minutes before rinsing) applied once daily for 3 consecutive days

1% Terbinafine solution applied twice daily for 1 week

1% Clotrimazole solution applied once daily for 1 week

Treatment of Tinea Versicolor with Oral Antifungals

Oral antifungal medications can cause side effects such as nausea or reversible liver damage, but these side effects are not common with the short courses of therapy used for tinea versicolor. Oral griseofulvin and oral terbinafine are not effective treatments for tinea versicolor.

The following oral treatment regimens have been shown to produce a greater than 70% clinical response rate:

Itraconazole 200mg every other day for 7 days

Ketoconazole 400mg single dose

Fluconazole 400mg single dose

Fluconazole 150mg or 300mg weekly for 4 weeks

Treatment of Tinea Versicolor with Dandruff Shampoos

Until recently, dandruff shampoos were the mainstay of treatment for tinea versicolor. They are less effective than the antifungal medications and can cause skin irritation, but they are available over the counter and are less expensive.

The following regimens have been shown to be effective:

Sulfur-salicyclic acid shampoo applied nightly as a lotion for 1 week

Zinc-pyrithione shampoo regimen (applied daily as a lotion and left on for 5 minutes before rinsing) for 2 weeks

Selenium sulfide 2.5% lotion regimen (applied daily as a lotion and left on for 10 minutes before rinsing) for 1 week