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Melasma (Chloasma) (Pregnancy Mask) Diagnostic elements, epidemiology and importance of sunprotection

Skin color is determined by:

  • The type of melanin
  • The amount of melanin in melanocytes
  • The distribution pattern in surrounding keratinocytes


The term melasma comes from Greek melas: black



Etiology: The exact cause is unknown but some factors play a role

  • Ultraviolet light (UV)
  • genetic factors
  • thyroid disturbances
  • cosmetics
  • hormonal factors (in females)




  • The incidence is unknown
  • It affects around 6 million people in the USA



The Prevalence is highest in

  • hispanics
  • East Asians
  • Individuals with Phototypes Fitzpatrick IV to VI
  • Individuals living in areas of intense Ultraviolet (UV) irradiation



Females are more affected than males:

  • female-male ratio 9 to 1
  • also men: 10% Caucasian, 26% Indians….




  • based on the depth of the pigment in the skin
  1. epidermal
  2. dermal
  3. mixed
  4. indeterminate
  • based on distribution
  1. centrofacial
  2. malar
  3. mandibular



Concerning the treatment of Melasma (Chloasma) (Pregnancy Mask): what one needs to know is that sun exposure, whether only once or repeated worsens melasma (chloasma)(pregnancy mask):

  • A single exposure to Ultraviolet light (UV) increases the size of melanocytes and tyrosinase activity.
  • Chronic exposure increases the number of melanosomes (organelles in melanocytes which contain melanin) and their transfer to the surrounding keratinocytes



Source of information: Handog E. Brown Spots: Melasma Updates.2012 (02) – 20th Regional Conference of Dermatology (RCD) – Manila, Phillipines


Source of information: here