What is tinea versicolor (pityriasis versicolor) and how does it present?

Tinea Versicolor (Pityriasis Versicolor): Clinical Description

Tinea versicolor is a common superficial fungal infection of the skin caused by Malassezia species (notably M. globosa, M. furfur, and M. sympodialis) that presents as scaly hypopigmented or hyperpigmented macules and patches, primarily on the upper trunk, neck, and upper arms 1, 2.

Causative Organism

The infection is caused by Malassezia species, which are normal skin saprophytes that convert from a yeast form to a pathogenic mycelial form under certain endogenous and exogenous conditions 2. This transformation results in mild inflammation and characteristic clinical changes.

Clinical Presentation

Lesion Characteristics

• Appearance: Scaly macules or patches that may be hypopigmented, hyperpigmented, or a combination of both 1, 3
• Color variations:
  • Hypopigmented lesions are most common, particularly in dark-skinned individuals (85.8% in one study) 4
  • Hyperpigmented lesions are more frequent in younger patients (<20 years: 70%) 5
  • Rare erythematous variants exist 6
• Scaling: Fine, characteristic scaling is typically present 1
• Size: Can present as either macules or larger patches 4

Distribution Patterns

• Primary sites: Upper trunk (chest and back), neck, and upper arms 1
• Age-related patterns:
  • Younger patients (<20 years) show more facial involvement (35%) 5
  • Shoulders affected in 7% of cases 4
• Rare presentations: Scalp involvement (often overlooked), folliculocentric, atrophic, and inverse forms 7, 8

Associated Features

Symptoms

• Usually asymptomatic or mildly symptomatic 1
• Mild pruritus reported in approximately 23.8% of patients 4
• More pruritus associated with larger patches than macular lesions 4

Predisposing Factors

• Excessive sweating (31.8% of patients) 4
• Oily/seborrheic skin (21.1% of patients, more common in younger age groups) 4, 5
• Occlusive clothing (19.4%) 4
• Outdoor occupation (57.5%) 4
• Warm, humid climates (most prevalent in tropics but common in temperate climates) 9
• Immunocompromised states 3

Epidemiology

• Age: Most common in young adults (mean age 27.6 years), but affects all age groups from children to older adults 5
• Gender: More common in males (69% in one study) 4
• Recurrence: High recurrence rate, with 60% of patients reporting recurrent episodes 4
• Family history: Positive in 33.6% of cases 4

Histopathological Features

Under light microscopy, Malassezia appears as a dimorphic fungus with both hyphae and yeast forms (described as "spaghetti and meatballs" appearance) 3. In dark-skinned individuals, lesions show thicker stratum corneum, more tonofilaments in the granulosum, and more sequestered melanosomes 3.

Differential Diagnosis

Key conditions to distinguish from tinea versicolor include 10:

• Vitiligo
• Pityriasis alba
• Pityriasis rosea
• Seborrheic dermatitis
• Confluent and reticulated papillomatosis
• Post-inflammatory hypopigmentation

Diagnostic Confirmation

Diagnosis is usually clinical based on characteristic features 1. When confirmation is needed, potassium hydroxide (KOH) preparation reveals numerous short, stubby hyphae intermixed with clusters of spores 1, 4. Wood's lamp examination may show yellow-gold fluorescence in some cases.