Post Operative Care of Lesions Treated with Liquid Nitrogen (Cryosurgery)
Patient Information Sheet
Freezing skin lesions with liquid nitrogen is often a good way to treat growths in the epidermis, the outer living layer of skin. It is routine for warts, actinic keratoses, seborrheic keratoses, and skin tags. It does not treat things below the epidermis such as moles. It is not adequate treatment for skin cancers.
The air you are breathing right now is 78.1% nitrogen. In 1895, a process was developed for chilling pressurized air so extremely that it turned to liquid. The liquid nitrogen component of liquefied air measures minus 196°C. By touching liquid nitrogen to the skin with a cotton-tipped applicator, the cells are frozen and brought to a temperature of -196°C (-321°F). That's pretty cold.
Living skin cells are about 78% water. By freezing them so severely & so quickly, particular kinds of ice crystal structures form from the water inside the cells. These ice crystals disrupt the delicate internal membranes of those cells and kill them. Ice cubes and dry ice (-70°C) are not cold enough to accomplish this. Liquid nitrogen is unique.
What to Expect:
Liquid nitrogen application will feel like a strong biting pinch for about 3 seconds. The pain quickly fades and is much better within 15 minutes. As the skin thaws out, the chilled nerves will recover function at different rates. This sometimes feels like something is dribbling on the skin for a few seconds, but there is nothing there. It is an illusion of the thawing out process. When I remove the cotton tipped applicator from your skin, there is nothing left on the skin. The frozen area may look like a mild hive for about 20 minutes. It's okay to scratch it. After two days, a scab will form. The scab will come off in about 10-14 days on the face and 1-2 months in other areas. Normal skin cells migrate in from the sides to heal the sore. The frozen area may heal to make a pink area, which usually returns to normal by about 2-4 months.
Rarely, a blister will form by the next day. It if does, cover it with a band-aid to protect it. I prefer not to make a blister. If the blister is tense and sore or if you just plain don't like it, I can withdraw the fluid for you using a sterile needle. This is optional, and it is okay not to drain smaller blisters. Just call my secretary and let her know. The destroyed epidermal cells form the roof of the blister. The normal new cells migrate in from the sides and cover the floor of the blister. This reestablishes the normal skin.
You will get the best cosmetic result if you leave the blister intact as long as possible. Do not break it or pierce it with needles or pins. The blister may be filled with clear fluid like water or with blood. Both of these are normal. The blister should not have pus in it. If pus develops, please tell me so I can give you antibiotic pills.
Risks and Complications:
I want to stress that cryosurgery usually goes well and heals well. One of the nice things about it is that liquid nitrogen is not a toxic chemical. It's the air you breathe. Although rare, a few problems can occur. By knowing what to look for, complications can be recognized early, dealt with, and thus they are less worrisome. If possible, try to schedule treatment for a time you will be home for a week or so rather than just before going on a trip or before an important social occasion such as a wedding.
- Soft tissue swelling: This occasionally occurs in lesions frozen around the eyes, forehead, and temples. Swelling may be alarming to patients and persist for weeks. I have never seen that happen in 34 years. Soft tissue swelling may be worse in the morning after lying down overnight when the blood is pooled more in the head. The swelling may then decrease during the day while you are up and walking about. Severe swelling is very rare.
- Infection: If pus develops in the treated area, you must call Dr. Tkach to get an antibiotic treatment. Generally, liquid nitrogen treatment does not leave scars. However, if infection occurs, the risk of scars is greater.
- Freezing of nerves: Rarely, small skin nerves running underneath the lesion being treated will be frozen by the liquid nitrogen. This may cause numbness in the areas associated with those nerves. This is a very rare complication, and in many instances the nerves will regenerate slowly. I have not encountered this problem in my patients. This is why I apply liquid nitrogen with a Q-tip instead of a spray can. The spray can application can freeze down to the bone. With the Q-tip application, such deep freezing is unlikely. It is slower using the Q-tip but safer.
- Headache: In rare instances, headache may follow freezing lesions around the temples and the scalp. This usually goes away within twelve to twenty four hours. For pain relief, take a non-aspirin medication such as Tylenol.
- Fever: I have not encountered this, but fever as high as 104°F has been reported. It is very rare. The mechanism of fever following liquid nitrogen treatment is uncertain. It may be a reaction to the destruction of treated tissue. The fever lasts about twelve hours and then usually goes away. To control this fever, you may take a non-aspirin medication such as Tylenol.
- Color change: Frozen areas usually heal leaving the color of the skin the same. Sometimes irritation from the treatment causes the area to darken for 2-4 months. If the treatment required was severe, it may leave a flat white area.
Rev. Jan. 27, 2010 copyright Dr. Tkach
The information provided in these patient information sheets is offered for general informational and educational purposes only; it is not offered as and does not constitute medical advice. In no way are any of the materials presented meant to be a substitute for professional medical care or attention by a qualified practitioner, nor should they be construed as such.