Thursday, 20 October 2011

Cryotherapy of a cherry angioma

Cherry angiomas (Campbell de Morgan spots) occur predominantly on the trunk and proximal parts of the limbs. Cryotherapy option, when treatment is required, works but it is a less-well controlled method than others.  

The freeze time BEGINS at the moment the target area of skin is COMPLETELY frozen (the ice ball). Liquid nitrogen is then sprayed intermittently on the target area to maintain the ice ball at the required margin. Liquid nitrogen spray is halted when the freeze time is up.

In cherry angiomas: Freeze time --> 10 seconds, lesions in general often need more than one freeze. Margin of normal skin also frozen (mm): 1

In larger lesions, the liquid nitrogen spray is directed from the side of the lesion
. This allows the extraneous liquid nitrogen to ricochet from the surface of the lesion into the air rather than over normal surrounding skin. If the larger lesion is sprayed directly from the top the extraneous liquid nitrogen will travel across the normal surrounding skin and invariably the physician will terminate cryosurgery before the central base of the lesion has been sufficiently frozen. 

The extent of injury is determined by the rate of freezing, the coldest temperature reached, the freeze time and the rate of thawing. Pain peaks during thawing. Use words like discomfort, burn, or pain whenever appropriate when describing the reaction so that the patient will know what to expect.