Why are white lesions white? Observations on keratin

Area of Science:

• Oral pathology
• Dermatology
• Biochemistry

Background:

• Oral lesions often present as white patches, a common clinical observation.
• The exact mechanism behind the white appearance of oral keratoses is not fully understood.
• Existing theories focus on keratin layer thickening, but this may not be the primary cause.

Purpose of the Study:

• To propose a mechanism for the white appearance of oral keratoses.
• To investigate the role of keratin hydration versus thickening in lesion whiteness.
• To identify areas for future research into the etiology of white oral lesions.

Main Methods:

• The study is theoretical, proposing a mechanism based on existing knowledge.
• It compares oral keratin to the stratum corneum's reaction to water.
• It analyzes the clinical significance of abnormal keratin accumulation.

Main Results:

• Oral keratoses appear white due to abnormal keratin's even light reflection, primarily caused by hydration.
• Keratin layer thickness is less critical than hydration for the white appearance.
• As little as 10-20 microns of abnormal keratin can cause a visibly white lesion.

Conclusions:

• Abnormal keratin hydration, similar to epidermal reactions to water, is the likely cause of white oral lesions.
• Further research is needed on lipids, granules, and intercellular cement for a complete understanding.
• Characterizing oral keratins and keratinization processes may reveal etiological and prognostic insights.