Overview of Cryotherapy in Dermatology
Cryosurgery, first introduced in the 1800s, is now a common method of treatment in the field of dermatology. It presents an efficient and economical option for treatment performed in an outpatient setting, avoiding the need for invasive surgeries. As no major incisions are made in cryosurgery, it usually leads to good cosmetic results.
In cryosurgery, tissues are frozen using a cooling agent, usually liquid nitrogen. This freezing kills the tissue in two ways. The first way is that it causes lack of blood flow to the tissue, which then dies. The second way is by creating ice crystals which damage the cells both inside and out, often causing them to burst. This damage continues even as the tissue thaws.
A better outcome of cryosurgery over surgical removal, especially for malignant cells (cells that could grow into cancer), is that it allows the body’s immune system to react to the dead cells. This helps the body to develop a wider immune response against these cancerous cells.
The damage to tissues increases with each freezing-and-thawing session. The ideal temperature to destroy benign (not harmful) cells is -20°C. Cells that can lead to cancer are generally harder to kill and require freezing to -50°C. However, cells that produce skin color (melanocytes) can get damaged at -5°C.
In cryosurgery, a concept called ‘isotherms’ is used. It means areas of same temperature while freezing. For example, if -5°C is maintained, all areas 10 mm away from the freezing center would be at the same temperature. This is useful for the surgeon to target a specific depth and temperature during the procedure.
Another point to note in cryosurgery is the aspect of conduction. The treatment’s efficiency may decrease if the liquid nitrogen is sprayed from a distance, as air acts as a poor conductor of heat. Also, tissues with thicker skin layer may need to be trimmed down for the treatment to work effectively.
Why do People Need Cryotherapy in Dermatology
Cryosurgery, which uses extremely cold temperatures to destroy abnormal tissue, is a method used to treat both harmful and non-harmful skin conditions.
Non-harmful skin conditions that can be treated with cryosurgery include seborrheic keratosis (skin growths that look like wax spots), verruca (warts), skin tags, molluscum contagiosum (a viral infection that causes small, benign skin lesions), solar lentigo (liver spots caused by sun exposure), and hypertrophic/keloid scars (scar tissue that’s thicker than the surrounding skin). Usually, these conditions can be treated with just one cryosurgery session. However, for larger or thicker growths or lesions, you may need to come back for more treatment sessions every 3 to 4 weeks until the growth or lesion is gone. This is particularly true for warts, which typically take 2 to 6 treatments to go away.
Cryosurgery can also treat pre-cancerous and cancerous skin lesions. This includes actinic keratosis (dry, scaly patches caused by sun exposure), basal cell carcinoma (a type of skin cancer), and non-invasive squamous cell carcinoma (another type of skin cancer). Cryosurgery has also been used to treat a type of skin cancer called lentigo maligna melanoma, but the success rate varies and sometimes the cancer comes back. Actinic keratosis is commonly treated with cryosurgery. Even so, cryosurgery is not the first choice of treatment when it comes to cancerous lesions. It’s usually saved for patients who aren’t suitable for surgery like senior patients who can’t tolerate operation, or for large lesions which would leave a disfiguring scar if surgically removed.
When a Person Should Avoid Cryotherapy in Dermatology
Cryosurgery, a procedure using freezing temperatures to destroy abnormal tissue, should not be conducted if your doctor is unsure of the nature of the abnormal growth. An accurate diagnosis must be made beforehand, typically through a tissue study (histologic diagnosis) or by clinical and dermatoscopic diagnosis, which involves examining the skin using special magnifying tools.
Further, there are other conditions where cryosurgery is not advised. If you have conditions that get worse with cold, such as cryoglobulinemia (a condition that causes blood proteins to clump together in the cold), multiple myeloma (a blood cancer), Raynaud’s disease (a condition that affects blood flow to the extremities causing them to turn cold), cold urticaria (a skin reaction to cold), or if you’ve had previous cold-induced damages in the area, cryosurgery might be risky.
Also, if there is poor blood circulation in and around the targeted area, cryosurgery isn’t a good option. This is because cryosurgery can cause blood vessels to narrow. If the blood flow is already restricted, this could lead to severe tissue death due to lack of blood supply.
Equipment used for Cryotherapy in Dermatology
Cryogens are substances used to create freezing temperatures. There are many different kinds of cryogens, but liquid nitrogen is the most commonly used. When we say ‘freezing,’ we mean really cold – liquid nitrogen boils at negative 196 degrees Celsius!
Liquid nitrogen is stored in special, heavily-insulated containers called dewars, which come in all sorts of sizes (from 4 to 50 liters). If properly stored, liquid nitrogen can last in these dewars for up to two months. If you need to make your own liquid nitrogen, you can use machines built just for that purpose.
So how does this connect to medicine? Well, doctors use cryosurgery, a type of treatment that uses extreme cold to destroy disease, like cancer. To perform cryosurgery, doctors use special tools that hold liquid nitrogen. These tools often come with different parts that can be changed out depending on what kind of treatment is needed.
For example, if your doctor needs to spray liquid nitrogen, they might use a spray gun-like tool that has various-sized tips depending on the size of the area needing treatment. They also have cone-shaped and flat tools of different sizes that can help focus the liquid nitrogen right where it’s needed. When the doctor needs to have direct contact for treatment, there are different sized probes that can be attached to the tools. There’s even a way to freeze other tools, like forceps or needle drivers, so they can be used to grip and treat certain kinds of growths.
When treating cancerous growths specifically, there’s an extra step to take – the doctor needs to know the temperature of the tissue being treated. Luckily, some of these tools have thermometers built right in to help the doctors know how cold it is at the place where the tool is touching. They can also use infrared thermometers together with spray cans, to help pinpoint temperature at various levels of the tissue they’re treating.
Preparing for Cryotherapy in Dermatology
Cryosurgery, a treatment that uses extreme cold to destroy abnormal tissues, doesn’t usually require a lot of skin preparation. In most cases, you won’t need antiseptic – a substance that prevents infection by killing germs. However, when the treatment is used for cancerous growths, especially using a contact probe (a device that touches the skin), an antiseptic should be applied to prevent potential bleeding.
Sometimes, if the abnormal skin growth is very thick, a doctor might scrape the area with a curette (a medical instrument), which helps the liquid nitrogen (the extreme cold substance used in the treatment) to work better and in a more precise way.
If the abnormal skin area being treated is small, a local anesthetic (medicine to numb the area) may not be needed as it might be more painful to inject than the treatment itself. Generally, cryosurgery on small skin areas is quite bearable.
However, when dealing with larger areas, a numbing cream can be applied a few hours before the treatment to help reduce any discomfort the freezing might cause. It’s worth noting though, that this may not be as effective for any pain experienced during the period when the treated skin area is warming up (thawing) after the treatment.
How is Cryotherapy in Dermatology performed
Cryosurgery is a procedure in which doctors use extreme cold generated by liquid nitrogen to destroy diseased tissue. The method varies depending upon the type of the skin lesion being treated.
For harmless, or benign, lesions such as keratinocytic tumors or pigmented lesions, a single freeze-thaw cycle is usually adequate, targeting a certain temperature depending on the type of lesion. However, verruca, known as warts, may be a bit tough to treat and may require a second freeze-thaw cycle at the doctor’s decision.
The process of ‘thawing’ refers to the time taken by the tissue to defrost and return to its original color after freezing. The ‘freeze-thaw’ cycle is repeated to ensure the maximum destruction of the damaged tissue. Generally, doctors prefer to avoid too much aggressive treatment in benign lesions to prevent complications like skin discoloration. These spots are usually be frozen until a white halo appears around the edges of the lesion to ensure the entirety of it is eliminated.
The duration of freeze time varies with the types of blemishes. For instance, solar lentigo, or sun spots, typically freeze around 3 to 4 seconds because melanocytes (cells in the skin that produce pigment) are more sensitive to cold injury. Here, care is taken to cover a bit area around the border of the lesion to avoid leftover pigmentation.
On the contrary, when it comes to actinic keratosis (rough, scaly patches on the skin caused by sun damage) or malignant (cancerous) lesions, cryosurgery isn’t the first choice. These kind of lesions are typically treated with two freeze-thaw cycles at a much lower target temperature. In these cases, it’s important to be more aggressive with the treatment as margin control cannot be guaranteed with cryosurgery. However, since there is no tissue sample taken after the procedure, it is important to ensure regular follow-up to keep an eye out for recurrence or regrowth of the lesion.
Cryosurgery could be administered in several ways like an open technique (spraying liquid nitrogen onto the lesion), semi-open technique (using a guide to direct the nitrogen to the targeted area), and closed (directly applying a liquid nitrogen-cooled probe to the skin). Doctors need to be cautious while using the probe because it may freeze to the skin during the procedure which can cause bleeding if removed forcefully.
In addition, for growths on stalks or pedunculated lesions, cooled forceps or needle drivers by liquid nitrogen are used to grasp them. This is another version of the closed or contact method.
Possible Complications of Cryotherapy in Dermatology
Cryosurgery, or freezing off unwanted or abnormal tissue, can have several outcomes that patients should know about before going through with it. After the treatment, the damaged tissue heals naturally which can take longer than healing from a cut, especially if the surgery is done on the leg. The healing time depends on how deep the freeze was, so if a lesion was frozen deeply, it will likely take longer to heal. Pain is normally felt during the procedure but it usually lasts less than a minute.
After the procedure, the treated sites change over several days, starting with redness and swelling, then small blisters may form. Depending on how deep the treatment was, some fluid might be seen coming from the site for up to 2 weeks. After this, the skin might get hard and dry, which can be gently scrubbed off if needed.
There are some complications that might happen after cryosurgery, like changes in skin color, hair loss, skin abnormalities, indented scars, and changes in the shape of the tissue. Changes in skin color are the most common complication, and more often the skin becomes lighter because the surgery can destroy the cells that give skin its color. However, in people with darker skin, the skin might turn darker. If the procedure is done on scalp or other areas with hair, hair loss might happen due to the freeze damage on hair follicles, and this could be permanent.
In a few cases, some skin abnormalities might occur after the procedure but they usually go away on their own without treatment. Deep freezing might lead to indented scars, but these might go away over time. Finally, cryosurgery can also damage underlying areas such as the nail bed of fingers and toes, or cartilage on the ears and nose, leading to changes in shape or indentations.
What Else Should I Know About Cryotherapy in Dermatology?
Cryosurgery is a skin treatment often used by doctors to manage benign (non-harmful) and malignant (harmful) conditions. It’s important for the doctor carrying out the treatment to know how cryosurgery works and how to apply it properly.
Before undergoing cryosurgery, your doctor should inform you about the procedure, why it’s suitable for you, and any possible problems that may occur. They should explain what results can be expected and prepare you for any potential risks associated with cryosurgery. This way, you can make an informed decision about proceeding with the treatment.
