Skin & hair

Freezing and Blistering: The In-Office Wart Options

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Beetle juice sounds like folk medicine, but cantharidin is an actual in-office wart treatment, and it works on a different principle entirely than the liquid-nitrogen freezing most people picture when they think of wart removal. Neither option is a guaranteed single-visit fix, and the research behind the more familiar of the two — cryotherapy — is thinner than its popularity suggests. Here's how each procedure actually works and what decides which one gets offered.

Last updated: July 2026

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Two Different Ways to Destroy a Wart

Cryotherapy and cantharidin are both destructive treatments — they work by damaging the wart tissue directly rather than fighting the underlying virus, the same broad approach as topical salicylic acid, which has the strongest trial evidence among the destructive options studied in a Cochrane review of topical and local wart treatments 1. Cryotherapy uses extreme cold, applied with liquid nitrogen, to freeze and kill the infected skin cells. Cantharidin works through the opposite mechanism — a chemical compound triggers the skin to form a blister that lifts the wart away as it heals. Both are performed in a clinician's office, and both usually take more than one visit to fully clear a wart, regardless of which is chosen. Choosing between the two in practice usually comes down to a mix of the wart's location, the person's age and pain tolerance, and simply what a given clinician's office is set up to offer, rather than one option being universally superior.

How Cryotherapy Works

Cryotherapy for warts uses the same liquid nitrogen freezing technique used for other skin lesions, applied directly to the wart with a spray device or a cotton-tipped applicator for several seconds at a time. The cold destroys the infected skin cells, and the treated area typically blisters, scabs, and sheds over the following one to two weeks. Documented adverse effects of cryotherapy include pain during and immediately after the procedure, blistering, and sometimes lasting lightening of the treated skin, particularly in people with darker skin tones 2. Multiple sessions spaced a few weeks apart are typically needed, since a single freeze rarely clears a wart completely on the first try. The freeze is typically held just long enough to create a small ring of ice around the wart's edge, since under-treating leaves infected tissue behind while over-treating raises the risk of scarring or a larger blister than intended.

What the Evidence Actually Shows

Despite being the treatment most people picture first for wart removal, cryotherapy's trial evidence is actually more limited and mixed than that of a much simpler option: topical salicylic acid, which a Cochrane review of local and topical wart treatments found has clearer evidence of benefit over placebo 1. That doesn't mean cryotherapy doesn't work — many people do clear warts with it — but it does mean the confidence behind recommending it isn't as strong as its popularity as the default in-office option might suggest. This is worth knowing before assuming a freeze at the dermatologist's office is automatically the most proven route, especially for a first attempt at treating a stubborn wart, since a lower-cost, lower-discomfort salicylic acid regimen at home has more trial data behind it. That same review found no clear evidence that combining cryotherapy with other treatments consistently improved outcomes over either approach alone, which is a useful reality check against assuming that more aggressive or combined treatment automatically works better.

How Cantharidin Works

Cantharidin is derived from a compound naturally produced by blister beetles, and in wart treatment it's painted directly onto the wart in a clinician's office, then covered and left in place for a few hours before being washed off at home. Unlike cryotherapy, applying cantharidin itself doesn't hurt — the discomfort comes later, as a blister forms under the wart over the following day, which is part of why it's often chosen for young children who can't tolerate the sting of freezing. The blister eventually breaks down the wart tissue as it heals, similar in end effect to what cryotherapy does, just by a different route and on a delayed timeline. The strength and duration cantharidin is left on the skin can be adjusted based on the wart's thickness and location, with thicker skin on the soles of the feet generally tolerating a longer application than thinner skin elsewhere.

What the Visit Itself Feels Like

The two procedures diverge most in timing and sensation rather than in the general concept behind them. Cryotherapy causes an immediate, sharp cold sensation during the freeze and residual soreness for a day or two afterward, all within the visit itself. Cantharidin application causes no pain in the office, but the blister that develops at home over the following one to two days can be uncomfortable or occasionally quite painful, and it requires a follow-up visit to check on the reaction and see whether the wart cleared. Choosing between them often comes down to how someone tolerates in-the-moment discomfort versus a delayed reaction, and for young children, cantharidin's painless application is frequently the deciding factor. Neither procedure is typically done under any form of sedation or numbing beyond what's built into the method itself, so the entire visit for either one usually takes only a few minutes of actual treatment time.

Not the Same as Genital Warts

The warts cryotherapy and cantharidin treat here are common skin warts — on hands, feet, and elsewhere on the body — which are a different category from anogenital warts. Anogenital warts are caused predominantly by low-risk HPV types 6 and 11, distinct from the HPV types most often behind common skin warts, and they're generally managed with a different set of treatment options 3. Anyone dealing with a wart in the genital area should be evaluated separately rather than assuming the same at-home or in-office approach used for a hand or foot wart applies.

When Neither Option Is Clearing the Wart

A wart that hasn't responded after several rounds of cryotherapy or cantharidin, or one that keeps recurring after appearing to clear, is a reasonable point to ask about escalation — options like stronger topical therapy, combination approaches, or referral to a dermatologist for a more resistant case. It's also worth a second look at whether the growth is actually a common wart at all: a lesion that's changed appearance, grown quickly, bled, or doesn't look like the surrounding lesions being treated as warts is worth having examined rather than assumed, since not every rough or raised bump on the skin is a wart. Persistent warts in someone who is immunosuppressed, whether from a medical condition or a medication, are also worth flagging specifically, since wart treatment in that setting can take longer and sometimes calls for a different approach entirely.

Common questions

During the procedure itself, yes — cryotherapy causes an immediate cold, stinging sensation, while cantharidin application is painless in the office. Cantharidin's discomfort comes later, when the blister it causes develops at home over the following day or two, which some people find more manageable and others find worse, since it isn't over quickly the way the freeze is.

Most warts need more than one session with either cryotherapy or cantharidin, often spaced a few weeks apart, since a single treatment rarely destroys all of the infected tissue. Some warts clear in two or three visits; others, especially larger or long-standing ones, take considerably longer.

It's commonly used in children specifically because the application itself doesn't hurt, unlike freezing. The blister that develops afterward can still be uncomfortable, and the treated area needs to be kept clean while it heals, but a clinician can adjust how long the compound is left on based on a child's skin and the wart's location.

Cryotherapy's trial evidence is actually more limited than commonly assumed, and warts can be genuinely resistant to repeated freezing. If several rounds haven't worked, it's reasonable to ask about switching approaches — topical salicylic acid, cantharidin, or a different combination — rather than continuing the same treatment indefinitely.

Over-the-counter freezing kits exist and use a milder cooling agent than the liquid nitrogen used in a clinician's office, so they tend to be less effective. Cantharidin is a prescription-only, in-office treatment because of how it needs to be applied and monitored, and it isn't available for home use.

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When a "wart" needs a second look

  • A growth that's changed size, shape, or color recently, rather than staying the same as other lesions being treated as warts
  • Bleeding, rapid growth, or a sore that doesn't heal where a wart is thought to be
  • A wart-like lesion in someone with a history of skin cancer or significant sun exposure
  • Signs of infection — spreading redness, warmth, or pus — after a cryotherapy or cantharidin treatment

This article is general health information, not medical advice. It cannot confirm that a specific growth is a wart or tell you which treatment is right for it. A dermatologist who has examined the lesion is the right source for that.

References

  1. 1.Gibbs S, Harvey I (2006). Topical treatments for cutaneous warts. Cochrane Database of Systematic Reviews. PMID 16855978Topical salicylic acid has clearer evidence of benefit versus placebo for cutaneous warts than cryotherapy, whose evidence is more limited and mixed.
  2. 2.American Family Physician (2007). Treatment Options for Actinic Keratoses. American Family Physician. linkCryotherapy with liquid nitrogen is a destructive lesion treatment whose documented adverse effects include pain, blistering, and hypopigmentation.
  3. 3.Centers for Disease Control and Prevention (2021). Epidemiology and Prevention of Vaccine-Preventable Diseases (Pink Book): Human Papillomavirus. CDC. linkAnogenital warts are caused predominantly by low-risk HPV types 6 and 11, a distinct category from the common cutaneous warts treated with cryotherapy or cantharidin.

3 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — citations link their sources. Editorial policy