Cryotherapy stands for “extreme cold therapy.” It is a technique that uses liquid nitrogen to freeze keloid and hypertrophic (raised) scars.1 Freezing can help to reduce raised scars in two ways:
- Killing old scar tissue: Freezing destroys some of the scar tissue that forms the raised scar. It also stimulates the formation of new scar tissue, which ideally will contain less collagen than the original scar, making the new scar smaller and more level with the surrounding skin.
- Reducing the number of fibroblasts: Fibroblasts are cells that produce collagen and other scar tissue components. Freezing kills some of the fibroblasts in the skin, which means that when new scar tissue forms to replace the destroyed scar tissue, the new scar will contain less collagen and thus be more level with the surrounding skin.2,3
Cryotherapy can be administered in one of two ways:
- Contact cryotherapy (rarely used): Liquid nitrogen is applied to the outside of the scar. This is an older method and is rarely used today, both because its efficacy is lower compared to intralesional cryotherapy, and because it carries a higher risk of side effects, such as skin lightening (hypopigmentation), blistering, delayed healing, and infection.
- Intralesional cryotherapy: Liquid nitrogen is injected into the scar using a thick needle called a cryosurgery needle. This method was first attempted in 1993 and has since become the dominant form of cryotherapy for raised scars. Because the liquid nitrogen is injected directly inside the scar, the treatment is more effective than contact cryotherapy, and because liquid nitrogen does not come into contact with the skin surface, patients experience fewer side effects compared to contact cryotherapy.2,3
As with all scar repair treatments, cryotherapy is sometimes combined with other scar repair procedures to achieve desired results.
People with active acne should not undergo acne scar repair of any kind, including cryotherapy. Ensure that your skin is clear of acne before beginning scar treatment.
Before agreeing to undergo cryotherapy, talk to multiple doctors about their opinions, proposed treatments, expected outcomes, and prices.
Contact cryotherapy: In contact cryotherapy, a doctor sprays the raised scar with liquid nitrogen from a hand-held pressurized container. The doctor holds the container a few centimeters (about an inch) from the skin surface and sprays the scar in a zigzag fashion.4
Intralesional cryotherapy: In intralesional cryotherapy, a doctor uses a cryosurgery needle to inject liquid nitrogen into the dermis of the scar.2 The dermis is the deeper skin layer that contains collagen.
For large scars, the doctor may need to insert the cryosurgery needle into the scar several times in different locations.5
Contact cryotherapy: Contact cryotherapy is mildly uncomfortable, as the extreme cold causes a stinging sensation on the skin. However, with small scars, the discomfort is short-lived and rarely requires anesthesia. For large scars, the doctor may choose to numb the skin by:
- Topical anesthesia: The doctor applies a dressing containing a numbing cream to the skin 1-2 hours before the procedure.
- Local anesthesia: The doctor injects an anesthetic into the skin prior to the procedure4.
Intralesional cryotherapy: Intralesional cryotherapy is somewhat painful and requires numbing the skin by:
- Local anesthesia: The doctor injects an anesthetic into the skin prior to the procedure5,6.
A keloid scar before (above, left) and 1 week (above, right), 6 weeks (below, left), and 12 months (below, right) after a single session of intralesional cryotherapy.5
- Levy LL, and Zeichner JA. Management of acne scarring, part II. A comparative review of non-laser-based, minimally invasive approaches. Am J Clin Dermatol. 13(5), 331-340 (2012).
- van Leeuwen MC, et al. Intralesional cryotherapy for the treatment of keloid scars: evaluating effectiveness. Plastic and Reconstructive Surgery Global Open. 3(6), (2015).
- Ledon JA, Savas J, Franca K, Chacon A, and Nouri K. Intralesional treatment for keloids and hypertrophic scars: a review. Dermatologic Surgery. 39(12), 1745-57 (2013).
- Rusciani L, Paradisi A, Alfano C, Chiummariello S, and Rusciani A. Cryotherapy in the treatment of keloids. J Drugs Dermatol. 5(7), 591-5 (2006).
- van Leeuwen MC, et al. Intralesional cryotherapy for treatment of keloid scars: a prospective study. Plast Reconstr Surg. 135(2), 580-9 (2015).
- Gupta S, and Kumar B. Intralesional cryosurgery using lumbar puncture and/or hypodermic needles for large, bulky, recalcitrant keloids. Int J Dermatol. 40(5), 349-53 (2001)
- Zouboulis CC, Rosenberger AD, Forster T, Beller G, Kratzsch M, and Felsenberg D. Modification of a device and its application for intralesional cryosurgery of old recalcitrant keloids. Arch Dermatol. 140(10), 1293-4 (2004).