melasma

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Fifth stage 

Dermatology 

Lec-12

 .د

  عمر

10/4/2016

Melasma

Biology of melanocyte 

  Dendritic cell at basal layer of epidermis 
  Produce melanin and send to surrounding keratinocyte 
  Epidermal melanin unit (melanocyte:keratinocyte) = 1:36 

Biology of melanin 

  Synthesis from melanosome 
  Transport to keratinocyte via dendritic process of melanocyte 
  2 type 

: eumelanin 
: pheomelanin 
 

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Melanin transfer 

  Phagocytosis 

 : melanin transfer to dermis 

 : phagocytose by melanophage 

  Endocytosis 

 : melanin transfer to keratinocyte via intercellular space 

Melasma 

  Acquired bilateral symmetrical hypermelonosis 
  Irregular light to gray brown macule and patch 
  Ill defined margin 
  Involved sun exposure area 
  Most common in women  
  Melasma is a common acquired pigmentary disorder that occurs mainly in women 

(more than 90% of cases) of all racial and ethnic groups, but particularly affects those 
with Fitzpatrick skin types IV–VI 

Distribution of melisma 

  Central facial pattern (63%) : cheek, forehead, nose, chin 
  Malar pattern (21%) : cheek, nose 
  Mandibular pattern (16%) :chin 

Cause of melisma 

  Light : UVA, UVB, visible light 
  Hormone : pregnancy, contraceptive pill 
  Drug : dilantin, anti-malarial drug, tetracycline, minocycline 
  Cosmetic : perfume, color 
  Genetic 
  Malnutrition : liver dysfunction, B12 def. 

Types of melisma 

  Epidermal melasma 
  Dermal melasma 
  Mixed epidermal dermal melasma 

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  The use of a Wood’s lamp can often be very beneficial in determining the location 

of melanin deposition showing enhancement of color contrast in lesional skin for 
the epidermal type, but not the dermal types. The mixed type has enhancement in 
some areas of lesional skin, but not in other areas.  

  Estrogen may play a role in melasma induction(OCP,HRT,pregnancy) 
  Pregnancy induced melasma will recover after some months (but not completely).  

Epidermal melisma 

  Light or dark brown color 
  Melanin deposition in basal, suprabasal layer of epidermis 
  Larger melanocyte with more noticeable dendritic process  

Dermal melisma 

  Blue gray color 
  Perivascular melanophage at superficial and middermis 
  Melanin granule in dermis 

Whether the melanin is deposited in the epidermis or dermis is important therapeutically 
because dermal hyperpigmentation is much more challenging to treat 

Topical Treatments for Melasma 

In those patients with epidermal type melasma, there are multiple treatments available 
(see Table 2).6 Topical agents include phenols, e.g., hydroquinone (HQ); retinoids, e.g., 
tretinoin; azelaic acid; kojic acid (KA); and glycolic acid (GA). 

Hydroquinon 

  2%–4% has been widely used for melasma therapy.  
   inhibits the conversion of dopa to melanin by inhibitin theactivity of tyrosinase. 
  may interfere with DNA and RNA synthesis, degrade melanosomes, and destroy 

melanocytes.  

Reports of contact dermatitis in up to 25% 

As an itchy eruption 

it is best to be tested in a hidden part before use 

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Side-effects included irritant and allergic contact dermatitis, PIH, nail bleaching and rarely, 
ochronosis-like pigmentation. 

Retinoids

  0.05-0.1% 
  inhibiting tyrosinase transcription,interrupting melanin synthesis. 
   While tretinoin may be effective in reducing melasma, it typically takes at least 24 

weeks to see clinical improvement.  

azelaic acid 

1) 15%–20%  a dicarboxylic acid, is a reversible inhibitor of tyrosinase  

2) shown to be as effective as HQ 4% but without its side effects. 

3) The combination of azelaic acid with 0.0a5% tretinoin or 15%–20% glycolic acid may 
produce earlier, more pronounced skin lightening. Adverse effects include pruritus, mild 
erythema, scaling, and burning. 

KOJIC ACID 

KA 2%  is generally equivalent to other therapies but may be more irritating. 

Glycolic acid 

  GA 5%–10% is an alpha-hydroxy acid  
  It decreases pigment by many mechanisms including thinning the stratum corneum, 

enhancing epidermolysis, dispersing melanin in the basal layer of the epidermis, and 
increasing collagen synthesis in the dermis.  

  HQ 5%, tretinoin 0.1%, and dexamethasone 0.1%, was first introduced in 1975 and 

termed the Kligman formula 

  combination of HQ 4%, tretinoin 0.05%, and fluocinolone acetonide 0.01% (Tri-Luma®, 

Galderma) proved better than any combination of two of the above agents, with 77% 
of patients showing complete or nearly complete clearing. 

Laser treatment for melisma 

  Target chromophore is melanin 
  Should destroy melanocyte in hair follicle 
  Good in dermal and mix melasma 
  Epidermal melanin removal : lPL 
  Dermal melanin removal : Q-switched Ruby, Q-switched Alexandrite, Q-switched 

Nd:YAG