Abstracts From New Zealand Dermatological Society Meeting 2025, Wellington, New Zealand

Melasma is a common, often distressing pigmentary disorder with well-established links to pregnancy and oral contraceptive use.However, its association with hormone replacement therapy (HRT) and in vitro fertilisation (IVF) remains underrecognised in the literature.With increasing use of these therapies, awareness of their potential pigmentary effects is essential.This review explores emerging evidence implicating HRT and IVF in hormonally induced melasma and proposes evidencebased management strategies.Oestrogen and progesterone may stimulate melanogenesis via tyrosinase upregulation and hormone receptor-mediated pathways.Case reports suggest that high-dose oral oestrogencontaining HRT may induce melasma, particularly in a forearmpredominant distribution with photoexposure.A small RCT using low-dose oestrogen showed no pigmentation change, though was limited by short exposure and low dosing.Facial melasma has been reported with topical oestrogens, while transdermal and vaginal formulations appear lower risk.Though direct evidence linking IVF to melasma is lacking, studies demonstrate increased hormone receptor expression in melanocytic lesions of IVF patients.We propose a clinical framework for prevention and management.Recommendations include cautious use of high-dose or prolonged oral HRT and topical oestrogens in at-risk patients.Management strategies centre on photoprotection (against UVB, UVA1, visible light), and gold-standard topical therapy with Kligman's formula.Effective alternatives include thiamidol 0.2% and cysteamine 5%, with adjunctive agents such as azelaic acid, kojic acid, alpha arbutin, and oral tranexamic acid.Glycolic acid peels and pigment-targeted lasers (e.g., picosecond, Q-switched) may be used judiciously, especially in skin of colour, due to risk of post-inflammatory hyperpigmentation.