Management of seborrheic dermatitis and pityriasis versicolor.

This paper is a review of two conditions (pityriasis versicolor and seborrheic dermatitis) which appear to both have a strong relationship to malassezia fungi.

General Information on Malassezia

• Malassezia is a lipophilic yeast family that requires lipids for optimal growth [1]
• It is a member of normal human skin flora and can be collected from almost all body areas
• All individuals have both a humoral and cellular immune response to malassezia [2]
• In certain conditions it has the ability to become pathogenic
• It has been blamed for a number of skin conditions
• Non-lipophilic malassezia have been identified (M. pachydermatis)
• It was first described in 1874 by Malassez (hence the name)
• Some researches still use it’s alias, pityrosporum ovale

Basics of Pityriasis Versicolor

• Pityriasis versicolor is considered a chronic superficial fungal disease [3]
• It is most common on the chest, neck and upper arms (in the tropics it is often seen on the face)
• In this condition the malassezia appears to change from it’s round blastospore form to the mycelial form
• High heat and high relative humidity are strong predisposing factors
• Incidence rates in tropical areas are estimated between 30% to 40% of the population, while the rate in lower temperature climates is estimated at only 1% to 4% [4]
• The disease is most common in the years when sebaceous glands are most active
• Recurrence rates after treatment are very high (60% after 1 year and 80% after 2 years)
• It is most often diagnosed through general clinical examination, but direct microscopy is much more effective
• Both internal and external factors are likely to play a big role in the disease

Common Pityriasis Versicolor Treatment Options

• A 50/50 mix of propylene glycol and water applied twice daily for two weeks is a simple, inexpensive and highly effective treatment method [5]
• Various topical anti-fungal shampoos and preparations have been shown to be effective. This includes:
• ketoconazole [6] and other azoles (bifonazole [7], clotrimazole [8], econazole, and miconazole [])
• zinc pyrithione [10]
• selenium sulfide (complaints regarding odor and stinging sensation exist)
• Ciclopiroxolamine 0.1%
• Terbinafine 1% cream formulation
• System therapy (oral anti-fungals) is typically on prescribed for more aggressive cases. Long term usage has serious risk of negative side effects. Some options include:
• Ketoconazole (oral)
• Itraconazole
• Fluconazole
• Even after successful treatment, it is recommended to continue a prophylactic regimen (due to high recurrence rates)

Basics of Seborrheic Dermatitis

• Seborrheic dermatitis most commonly affects the scalp, eyebrows, nasolabial folds, cheeks, ears, upper chest, and groin region
• Seborrheic dermatitis lesions are often red and covered with greasy scales
• Incidence rates are reported between 2 to 5%
• Incidence rates are much higher in individuals with pityriasis versicolor, malassezia folliculitis, parkinson’s disease, major truncal paralysis, mood depression, AIDS and HIV infection
• It is typically starts during puberty and can return during the later stages of life
• It is commonly referred viewed a s a chronic condition with recurring flare ups
• Stress, dry air and a genetic predisposition appear to be important factors in disease progression and state
• Many studies indicate malassezia plays an important role [11]
• Studies examining the connection between seborrheic dermatitis, malassezia and the immune system are abundant, but much of the results conflict one another
• The immune system’s response in seborrheic dermatitis is likely altered and plays a significant role [12]
• In individuals with neurological diseases (particularly immunosuppressive disorders) the condition is more resistant to treatment

Common Seborrheic Dermatitis Treatment Options

• Mild corticosteroids are effective, but symptoms usually rapidly relapse following treatment
• Antifungal therapy is the current preferred treatment approach and has been shown to be better suited for long term treatment. Common anti-fungals include:
• Ketoconazole appears to have some of the best anti malassezia activity in the lab
• Zinc pyrithione
• Selenium sulfide
• Bifonazole
• A propylene glycol solution and a shampoo have also been shown to produce good results [13]
• In severe cases of seborrheic dermatitis, topical anti-fungal treatment alone may not be as effective. Oral treatment attempts may be prescribed
• Maintenance treatment is often recommended to prevent recurrence

Research Paper Details