Conference Notes
Hyperpigmentary Disorders in Children
Sunday, May 13th, 2012Pigmentary disorders are frequent in children and can result in significant psychosocial problems. Hyperpigmentary disorders can be classified into melanocytes problems (epidermal, dermal) and neurocutaneous disorders presenting with pigmentation problems. Giant congenital nevus carries a low risk of malignant transformation (melanoma) but it is important to exclude cutaneous neuromelanosis in high risk patients. Malignant lentiginosis […]
Synthesis of Melanin and its Disturbances
Sunday, May 13th, 2012Melanin is produced by mature melanocytes. The biosynthesis of melanin is a complex which implicateds numerous enzymes which include tyrosinase, TRP1, TRP2…Genetic disturbances of these enzymes can result in a pigmentary dilution which translates clinically with depigmentation as is seen for example in oculocutaneous albinism. The production of melanin is done within melanocytes in organelles […]
The Role of Keratinocytes in Disorders of Pigmentation
Sunday, May 13th, 2012From the extremities of dendritic melanocytes, melanosomes are transfered to the neighbouring keratinocytes. However, the mechanisms implicated in this transfer are not well understood but involve an intimate contact between a melanocyte and a keratinocyte (in the epidermis). This in turn implies the presence of cell membrane proteins. The incapacity to do this explains the […]
Hypopigmentary Disorders in Children
Sunday, May 13th, 2012Pigmentary disorders are frequent in children and can result in significant psychosocial problems. Hypopigmentary disorders may be caused by absence or reduction of the number of melanocytes. They can also be caused by the reduction or absence of production of melanin (with a normal number of melanocytes). Vitligo is a skin disorder which is clinically […]
Oral Tranexamic Acid in the Treatment of Melasma (Chloasma, Pregnancy mask): a Summary
Sunday, May 13th, 2012Oral tranexamic acid taken orally is effective in the treatment of melasma (chloasma, pregnancy mask) refractory to topical combination treatment. These results are supported by evidence from previous studies frm Japan and South Korea. Tranexamic Acid (trans-4-aminomethylcyclohexanecarboxylic acid) is an anti-fibrinolytic agent which inhibits the activation of plasminogen by reversible blockade of lysine-binding molecules on […]
Melasma (Chloasma, Pregnancy Mask): Why is it so difficult to treat ?
Sunday, May 13th, 2012One of the reasons to this therapeutical frustration is due to the lack of understanding of the pathogenesis of melasma (chloasma, pregnancy mask). Although triggering factors (ultraviolet light, pregnancy, oral contraceptives) and immunohistochemical properties of melasma are well known, molecular and genetic mechanisms which are involved a poorly understood. Scientific Consensus says the following about […]
Migration of Melanocytes during Melanogenesis
Sunday, May 13th, 2012Melanocytes originate from the neural crest. During early embryogenesis, melanocyte precursors migrate from the neural crest to the epidermis in a dorsolateral fashion. This migration is also done to the internal ear. This migration pathway and the maturation of the melanoblasts are regulated by a variety of factors, which included tyrosinase receptors such as c-kit. […]
Confocal Microscopy
Thursday, April 19th, 2012Known in full as Reflectance Confocal Microscopy (RCM). At time of publication it is still in development phase but it shows promising results How does it work ? It consists of the measurement of a reflection from a laser (monochromatic light) which reaches the dermis (Vivascope is a device brand). When can it be used […]
Kojic acid
Wednesday, March 21st, 2012Kojic acid It is a fungal metabolite which inhibits the enzyme tyrosinase. It binds to copper which becomes unusable by melanocytes. It is used at a concentration of 1% Its therapeutical effets are weak to moderate. Contributors: Dr Christophe HSU – dermatologist. Geneva, Switzerland Bibliography: Katsambas A. Melasma: Pathogenesis and Treatment. 70th Annual Meeting of […]
Hydroquinone (HQ)
Wednesday, March 21st, 2012Hydroquinone (HQ) Mechanism of action: hydroquinone inhibits activated tyrosinase activity (therefore it does not act on normal skin). A word on available concentrations: 2%: often ineffective 3-5%: good bleaching agent 6-10%: higher concentrations can cause irritation Side effects: Contact dermatitis (Both Allergic and Irritant) Nail Discoloration Exogenous Ochrnosis can rarely occur in dark skin individuals […]
