Does Hormone Replacement Therapy Influence Melasma Development? A Review of the Evidence and Management Guidelines

Area of Science:

• Dermatology
• Endocrinology

Background:

• Melasma is a common hyperpigmentation disorder influenced by UV exposure, genetics, and hormones.
• While associations with pregnancy and oral contraceptives are known, hormone replacement therapy (HRT) impact is under-researched.

Purpose of the Study:

• To evaluate evidence linking HRT and melasma.
• To propose evidence-based management guidelines for HRT-associated melasma.

Main Methods:

• Conducted a literature search of PubMed, Embase, and Scopus.
• Included studies on various HRT formulations: oral estrogen-only, combined HRT, transdermal, topical, and vaginal estrogen.
• Developed guidelines based on evidence strength.

Main Results:

• Limited evidence, primarily case reports.
• High-dose oral estrogen-only HRT has the strongest documented association, particularly for forearm melasma in Fitzpatrick types III-VI.
• Case reports exist for combined oral and transdermal HRT; topical and vaginal HRT have minimal evidence. In vitro fertilization showed no association.

Conclusions:

• HRT-associated melasma is underrepresented in literature.
• Clinicians should counsel at-risk women on melasma and emphasize photoprotection.
• Prospective studies are needed to clarify risks across different HRT formulations.