Melasma (sometimes referred to as chloasma or the
mask of pregnancy) is a common, acquired disorder of
hyperpigmentation affecting millions of people worldwide.
The differential diagnosis for melasma is wide, and includes
acquired nevoid disorders, reactions to medications, interface
dermatoses, lichenoid dermatoses and age-related skin
changes. It is imperative to make a correct diagnosis of
melasma prior to embarking on treatment.
The pathogenesis of melasma is not well understood, but
recent studies have discovered new signaling pathways that
may play a role in melasma and which could be targeted
with new therapeutic agents. While the role of ultraviolet
light in causing melasma is well known, recent studies have
pointed to visible light as an etiologic factor as well.