▶ Previous Artlcle: #10-3. Q-switched Ruby Laser 

 

 

The procedure is performed by using the 2mm spot size for freckles, but the procedure for large superficial pigment lesions such as lentigo and café au lait spot commonly involves the use of the 4mm spot size.

 

If possible, it is desirable to avoid overlapping the spots. Even if the spots overlap, they should overlap less than approximately 10%.

 

Fluence varies depending on the lesion, and is appropriate insofar as it is limited to mild whitening.

 

The whitening arises from large temperature difference between normal tissue and pigment occurs immediately after irradiation of Ruby Laser, and subsequent rapid thermal expansion creates vacuole which in turn causes scattering of light.

 

 

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Bleaching usually disappears within an hour, and followed by occurrence of erythema and edema which usually last from a few hours to 24 hours. Later, crust occurs.

 

The crust on the face remains for 7-10 days, while the crust on the body lasts for 14-20 days, and is naturally exfoliated at the re-epithelialization of the tissue underneath the skin.

 

Ecchymosis or epidermis burst may occur during the procedure if the spot size is made even larger or fluence is increased excessively.

 

 

Figure 1. Hyperpigmentation 

 

 

Consequently, hyperpigmentation or hypopigmentation becomes excessive, prolonging the recovery time, and additional measures may become necessary due to patient's complaint over side effects.

 

So, it is recommended that excessive procedure should be avoided.

 

For dermal pigmented lesions, such as tattoos (black, blue, azure, green), ABNOM, Ota nevus, and Ito nevus, it is also recommended to select the 4mm spot size for irradiation that limits the extent of fluence to mild whitening. 

 

 

-To be continued