Symptoms
Pityriasis versicolor is a skin disorder that occurs primarily on areas with high sebum production, such as the back, chest, upper arms, shoulders, armpits, neck, face, and scalp. Round to oval hyper- or hypopigmented patches occur. The skin is slightly thickened, scaly, and sometimes mildly itchy. The patches may be colored, for example, pink, salmon, brown, red, or black. When they are hypo- or depigmented, they are also referred to as pityriasis versicolor alba.
Causes
The cause of the disease is a superficial fungal infection of the stratum corneum with yeasts of the genus , especially with . These unicellular and lipophilic fungi are a normal part of the skin flora in all people, but only in some they cause clinical symptoms due to endogenous and exogenous factors.
Risk factors
Fungal growth is favored by a warm, moist, lipid-rich environment. Adolescents and younger adults are therefore more likely to be affected because they produce more sebum, and the condition occurs more often in countries with a tropical climate. Sweating is also thought to promote the condition, and heredity probably plays an important role (common in first-degree relatives). Other factors, such as immunosuppression, are discussed.
Diagnosis
Diagnosis can usually be made by an experienced dermatologist based on the clinical picture. In addition, a microscopic test is performed. Skin scales are dissolved with potassium hydroxide (KOH) and a little heat and stained with methylene blue, for example. Under the microscope, this makes the round spores and the filamentous pseudohyphae visible (also known as “spaghetti with meatballs” in the jargon, corresponding illustrations can be found in the specialist literature). In some of the patients, the lesions fluoresce under UV irradiation (Wood light, 365 nm or in disco).
Diagnosis
The diagnosis is made under medical treatment. Differential diagnoses include other pigmentation disorders such as vitiligo, but it occurs mainly on the hands and face. Other skin diseases such as chloasma, tinea corporis, seborrheic dermatitis, pityriasis rosea, erythrasma, or syphilis must be excluded from the diagnosis.
Drug treatment
Topical antifungal agents:
- Since it is a fungal infection, antifungal drugs are used for treatment. Azole antifungals such as econazole, miconazole, clotrimazole, or ketoconazole, as well as ciclopirox or terbinafine, are used for external treatment. Since the disease often occurs over a large area, treatment with a solution or shampoo is advantageous (eg, ketoconazole).
Systemic antifungals:
- Internally, fluconazole, itraconazole or ketoconazole are used. These drugs must be prescribed by a physician and may cause more adverse effects than local therapy. In addition, it must be noted that it is not suitable for all patients. An advantage, on the other hand, is the simpler application.
Topical keratolytics:
- Such as selenium disulfide, zinc pyrithione, sulfur or salicylic acid are corneal dissolving agents that can also affect sebum production and some have antimicrobial activity. They are used in the form of shampoos or as a suspension.
It should be noted that the spots may persist for weeks to months after successful treatment, especially if they are de- or hypopigmented.
Prevention
Because recurrences are common, antifungals and keratolytics are also used preventively. For example, the literature suggests using selenium disulfide for the first three days of each month. Prophylaxis is also possible with internal or external antifungal agents.
