Skin Barrier Function and Its Relationship With IL-17, IL-33, and Filaggrin in Malar Melasma

Area of Science:

• Dermatology
• Skin Biology
• Immunology

Background:

• Melasma pathogenesis is unclear, but inflammation and barrier disruption are implicated.
• Interleukin-17 (IL-17) is a proinflammatory mediator affecting barrier function.
• Filaggrin (FLG) is vital for epidermal barrier homeostasis and may be influenced by IL-17 and IL-33.

Purpose of the Study:

• Evaluate epidermal barrier function in malar melasma.
• Assess the association between melasma and the expression of FLG, IL-17, and IL-33.

Main Methods:

• Assessed barrier function using colorimetry and transepidermal water loss (TEWL) via tape stripping in 20 melasma patients.
• Analyzed FLG, profilaggrin, IL-17, and IL-33 expression in melasma and perilesional skin biopsies using immunohistochemistry and RT-qPCR.

Main Results:

• Melasma skin showed higher erythema and TEWL post-stripping compared to unaffected skin.
• FLG and IL-17 expression were elevated in melasma lesions, positively correlating with each other.
• IL-33 expression was higher in adjacent normal skin than in melasma lesions.

Conclusions:

• Melasma exhibits subclinical inflammation adjacent to lesions and epidermal barrier dysfunction.
• Chronic inflammation in melasma is linked to impaired barrier function and abnormal FLG differentiation.
• Maintaining facial stratum corneum integrity is essential for melasma management.