Section : Conference Notes

Melasma (Chloasma) (Pregnancy Mask): Epidemiology and Risk Factors


  • melasma comes from the Greek word “melas” which means black
  • chloasma comes from the Greek word “chloe” which means green grass


  • Geographical Factors
  1. affected 5 million people in the USA in 1955
  2. affects 8.8% of Latino (Hispanic) females
  3. affects 40% of females in South-East Asia
  4. affects 80% of males in South-East Asia !
  • Gender Factors
  1. women are affected 9 times more often than men

Clinical characteristics

  • dark skin Types (III and above) are affected more than fair skin-types
  • distribution usually symetrical
  • the color can be light brown, dark brown, grey brown
  • localized on the face sometimes on the neck

Risk factors

  • skin type more of than Fitzpatrick type III
  • genetic background
  1. 48% of affected patients report a family history
  2. 54.7% of affected patients in an Iranian study report a family history with a first degree relative affected
  • Hormonal hyperestrogenic states
  1. oral contraceptive pill
  2. pregnancy (thus the term pregnancy mask)
  3. estrogen receptors have been found in melanocytes of melasma lesions
  • Sun exposure
  1. melasma is worse with sun exposure
  2. melasma fades after sun avoidance
  3. melasma repigments more than the inital lesion if one is re-exposed to the sun
  4. UV radiation promotes the following: Interleukin 1 (Il-1), Endothelin 1, Alpha MSH, ACTH…more than 1500 genes are involved

more blood vessels in melasma lesions compared to perilesional skin

When does it appear ? (study by Ortonne JP et al.)

  • mean age of onset: 34 years old
  • a family history is reported by 48% of affected patients (of which 97% are first degree relatives)
  • The overwhelming majority has a skin type of more more than III
  • 42% of new melasma cases were during pregnancy
  • 25% of new melasma cases were under oral contraceptive treatment


Dr Christophe HSU – dermatologist. Geneva, Switzerland

Source of information:

Katsambas A. Melasma: Pathogenesis and Treatment. 70e Réunion annuelle de l’AAD (American Academy of Dermatology) – San Diego, California, United States of America (USA)

SY 20. Hyperpigmentation. Katsambas A. Melasma Pathogenesis and Treatment. What’s New ? 2012 (06) – 9th Spring Symposium of the EADV (European Academy of Dermatology and Venerology) – Verona, Italy (Italia)