Tinea versicolor: ultrastructural studies on hypopigmented and hyperpigmented skin

Area of Science:

• Dermatology
• Mycology
• Cell Biology

Background:

• Tinea versicolor is a superficial fungal infection caused by Malassezia furfur.
• The infection presents with varied pigmentation, including hypopigmented and hyperpigmented macules.
• Understanding the cellular mechanisms behind these pigmentary changes is crucial.

Purpose of the Study:

• To investigate the ultrastructural alterations in the skin of patients with tinea versicolor.
• To compare these changes in hypopigmented, hyperpigmented, and uninvolved skin sites.
• To elucidate the role of Malassezia furfur in the observed pigmentary changes.

Main Methods:

• Punch biopsy specimens from four tinea versicolor patients.
• Analysis using light, scanning, and transmission electron microscopy.
• Comparison of ultrastructural features across different pigmented and uninvolved skin sites.

Main Results:

• Hyperpigmented skin showed a thicker stratum corneum than hypopigmented and uninvolved skin.
• Hypopigmented skin had dispersed, fewer melanosomes, while hyperpigmented skin showed sequestered melanosomes, indicating impaired transfer.
• Cytoplasmic organelles were affected in both pigmentation types, with latent effects on the nucleus and nucleolus.

Conclusions:

• Malassezia furfur infection leads to significant ultrastructural changes in keratinocytes.
• Both hypopigmentation and hyperpigmentation in tinea versicolor appear to be intermediate stages of cellular response to fungal invasion.
• These findings provide insight into the pathogenesis of pigmentary alterations in tinea versicolor.