What is Cryotherapy?
Cryotherapy, also known as cryosurgery, is one of the popular dermatologic procedures. It is cheap, easy to use and gives good cosmetic result. Because of its fewer side effects, ease of use and good results, it has been the treatment of choice for many of the skin lesions like seborrheic keratosis, actinic keratosis, skin tags, warts, molluscum contagiosum, dermatofibroma etc.
How does Cryotherapy works?
Though there are several cryogen liquids, liquid nitrogen is the most commonly used cryogen because of its low boiling point and ease of use. Cryotherapy is done in doctors’ office and need no special preparation. Your doctor may apply liquid nitrogen with the help of spray gun, a metal probe or a cotton bud. When liquid nitrogen is directly applied to the lesion for few seconds, as per required depth and area of freeze, the targeted tissue is frozen resulting is tissue injury. This procedure lasts few seconds and need no local anesthesia. For more extensive and large lesion local anesthesia may be applied prior to procedure.
After the skin has frozen, it turns white and it takes 2-3 minutes to thaw to normal skin temperature. Rapid freezing and slow thaw causes maximum tissue damage and is most suitable for the treatment of malignancies. While, rapid thaw causes fibroblasts to produce less collagen, which is more useful in the treatment of hypertrophic, keloids or benign skin lesions in areas prone to scarring.
As cryotherapy treatment causes our skin’s basement membrane to separate, this results in blister formation. The area that has been treated is most likely to blister within few hours. Blistering may be associated with clear, read or bloody fluid inside it, which is normal and harmless. Some individuals may experience mild to moderate pain at the site following the treatment. Oral acetaminophen or other NSAID’s may be taken if pain persists for longer period.
After few days blister dries up and scab forms. No any special treatment is needed during healing process. Just make sure to keep the area clean. You may gently wash the area once daily. If the procedure is done on the area of repetitive friction, dressing to the wound may be done to avoid trauma. Although secondary infection is rare, please consult your doctor if you experience pain, swelling, redness and discharge from the site.
The scab on the face usually peels off after a week, while, it may take 2-3 weeks for hands and even more 2-3 months for the scab on the lower limbs, as healing is often slow on the lower limbs.
Is Cryotherapy Safe for Everyone?
Although well tolerated with less side-effects cryotherapy is not for everyone. Cryotherapy is not suitable for patients with cold tolerance, cold urticaria, cryoglobulinemia, history of Raynaud disease and pyoderma gangrenosum. Please talk to your doctor about your present and past history if you have any.
Cryotherapy Side Effects
Although safe, cryotherapy may still leave hypopigmentation, especially on dark skinned individuals. Complications can be divided into 4 sub-groups:
- Prolonged but temporary
Immediate complications may include mild headache, blister formation and pain in the site.
Delayed complications may include hemorrhage, infection, and excessive granulation tissue formation. Infection although rare, is more likely to occur on lower legs as it takes more time to heal on lower limbs.
Prolonged but temporary complications include pigmentary changes (both hypopigmentation and hyperpigmentation), change in sensation and milia which gradually fades after few months.
Permanent complications are very rare but include nerve damage, alopecia, atrophy, keloids, scarring and hypopigmentation.