OsteopPityriasis (Tinea) Versicolor (Pediatric)orosis

Definition

Pityriasis versicolor is a superficial fungal infection of the skin caused by Malassezia species, presenting with hypo- or hyperpigmented, scaly macules and patches, predominantly affecting the trunk and proximal limbs in children.

Epidemiology

• Common in adolescents and pre-adolescent children, especially in tropical and humid climates
• Peak incidence between ages 10–16 years
• No significant gender predilection
• Incidence increases in hot, humid seasons
• Recurrence is common due to persistent skin colonization by Malassezia

Etiology

• Malassezia species (formerly Pityrosporum), a lipophilic yeast normally present on skin
• Predisposing factors: warm, humid climate, excessive sweating, oily skin
• Immunosuppression or corticosteroid use can exacerbate infection
• Genetic susceptibility may contribute
• Malnutrition or systemic illness may increase susceptibility

Pathophysiology

• Malassezia yeast proliferates in stratum corneum under favorable conditions
• Yeast produces azelaic acid and other metabolites, causing localized inhibition of melanocytes leading to hypopigmentation
• Inflammatory response is minimal; scaling is often subtle
• In some cases, overgrowth leads to hyperpigmented patches
• Recurrence occurs due to persistence of yeast on skin surface
• Secondary bacterial infection is uncommon