Cantharidin vs Cryotherapy

Cantharidin: A liquid made from a blister beetle extract, painted onto molluscum bumps or warts in the office and washed off at home at a set time. It causes a small, controlled blister that lifts the lesion off. Putting it on does not hurt, which is why it suits young children. The blister that follows can.

Cryotherapy: Liquid nitrogen is sprayed or dabbed onto a spot to freeze and destroy it. It is a standard treatment for warts, precancerous sun spots and some harmless growths. It commonly leaves a pale mark that does not fully come back.

Reviewed by Dr. Schwarz, Board-Certified Dermatologist
Last updated: 10/22/2026

Editorial illustration for Cantharidin, based on the entry’s treatment or equipment reference.

Editorial illustration for Cryotherapy, based on the entry’s treatment or equipment reference.

Choose if Key differences What is it?What it treats Treatment areas Skin tones How it works Before your treatment Day of treatment After your treatment Risks Cost Questions Related

Choose Cantharidin if…

Choose for molluscum or warts in young children who won't tolerate freezing or scraping — painless to apply.

A child with molluscum or warts
You want nothing sharp or cold
You can wash it off at home on time

Choose Cryotherapy if…

Choose for quick removal of warts, sun-damage spots or harmless growths — accepting a possible pale mark.

A wart or rough sun spot
You want it done in one quick visit
A pale mark wouldn't bother you

Alternatives, not combined

Can you have both?

Both treat warts and molluscum. Cantharidin is painless to apply and suits children; cryotherapy freezes the spot. One is usually chosen per spot.

Key differences

● Cantharidin

● Cryotherapy

DowntimeNone → 2+ weeks

3–7 days

1–2 weeks

PainMinimal → Needs anesthesia or sedation

Mild

Results showImmediately → 3+ months

1–4 weeks

How long it lastsWeeks → Years or permanent

Years or permanent

Visits neededOne → Every few months

A short series (2–3)

Cost per visit$ → $$$$$

ReversibleYes, can be undone → No, permanent

No, permanent

What is it?

Cantharidin

Cryotherapy

What is it?

It is a blistering agent.

Cantharidin is applied to selected lesions by a clinician.

It treats molluscum.

YCANTH is approved in the US for molluscum from age two.

It is not a home product.

It is not a wart-removal liquid for home use.

It is toxic.

It must be kept away from the mouth and eyes.

It freezes tissue.

Liquid nitrogen destroys selected tissue through freezing and thawing.

It treats diagnosed lesions.

It is used for benign or precancerous spots.

It leaves no specimen.

Nothing remains for microscopic examination.

Uncertain moles should not be frozen.

A diagnosis is needed first.

What it treats

Evidence level

Cantharidin

Cryotherapy

Strong evidenceMost established uses

A cluster of firm, dome-shaped pink and pearly white bumps on the side of a child's trunk on light skin, each two to five millimetres across with a small dip in the center.

Molluscum Contagiosum

Approved for molluscum.

A rough, dome-shaped wart on the side of a finger on fair skin. The bump is pinkish with a thin red ring at its base, and several tiny black dots are clearly visible in the thickened surface.

Warts

A first-line treatment.

Actinic Keratosis

Clears precancers.

Two growths on the upper back on fair skin. One is a flat light tan patch and the other is a raised mid-brown growth with a rough waxy surface and a sharply defined edge.

Seborrheic Keratosis

Removes growths.

Moderate evidenceSome supportive research

Warts

Lifts warts off.

AI-generated educational illustration: A small soft hanging skin growth on light skin.

Skin Tags

Freezes small tags.

Little evidence

—

A raised, smooth, firm scar on the upper chest on light skin. It is shiny pink-red and hairless, and its edges spread well past the small mark it grew from.

Keloids

Injections work better.

Not effective

Skin Tags

Not used for tags.

Moles

Not for moles.

Melanoma

Needs excision.

Treatment areas

The specific lesion, scar or affected patch determines the treatment site; there is no fixed body distribution.

Skin tones

Skin tone

● Cantharidin

● Cryotherapy

Lighter skin

Low risk

Pink marks fade.

Some risk

A pale mark may not fully return.

Medium skin

Some risk

Temporary darker marks.

Some risk

Pale or dark marks are more visible.

Deeper skin

Some risk

Darker or lighter marks may take months to fade.

Higher risk

Lasting pale patches are common; ask about alternatives.

How it works

Cantharidin

Cryotherapy

How it works

Cantharidin mechanism diagram. Medicine is placed on the lesion: Cantharidin is applied to a carefully selected skin growth. A local blister forms: Superficial skin cells separate within the treated area. The area heals: The treated surface sheds and heals; more treatment may be needed.

Cryotherapy mechanism diagram. A selected lesion is frozen: A clinician applies liquid nitrogen to the treatment area. Cold injures the tissue: A controlled freeze-thaw response damages the target. The treated area sheds and heals: A blister or crust may form; repeat treatment can be needed.

Diagram explanation

Medicine is placed on the lesion: Cantharidin is applied to a carefully selected skin growth. A local blister forms: Superficial skin cells separate within the treated area. The area heals: The treated surface sheds and heals; more treatment may be needed.

Schematic illustration. Technique and response vary. This explains a mechanism and does not specify treatment settings.

A selected lesion is frozen: A clinician applies liquid nitrogen to the treatment area. Cold injures the tissue: A controlled freeze-thaw response damages the target. The treated area sheds and heals: A blister or crust may form; repeat treatment can be needed.

Schematic illustration. Technique and response vary. This explains a mechanism and does not specify treatment settings.

Before your treatment

Cantharidin

Cryotherapy

2–4 weeks before

Before you book: Plan ahead: Work out when the wash-off falls and whether you will be near soap and water.

Not specified

The week before

A few days before: Actives: Skip salicylic acid, retinoids and strong exfoliants on the area.

A few days before: Thick warts: Soaking and filing the wart with a pumice stone or emery board helps the freeze reach the wart, not the callus on top.

Ask your provider: Several spots: If more than one spot is planned, ask to start with one and see how the skin heals.

Day of treatment

Cantharidin

Cryotherapy

Before you arrive

Clean skin: Clean, dry skin.

Not specified

Arrival & prep

The lesions are counted and the provider decides how many to treat today.

The spot is examined first — the most important part of the visit.

Treatment

Liquid is dabbed onto each bump with a wooden applicator, touching only the lesion, and air dries for a minute or two.

Some providers tape a wart afterward, which makes it stronger and changes the contact time, so ask. Several lesions take 5 to 15 minutes. You feel nothing during the visit; the discomfort comes hours later as the blister forms.

Liquid nitrogen is sprayed or dabbed on until a white frozen halo covers the spot and a small margin.

A sun spot takes seconds; a wart takes longer and is usually thawed and frozen again the same visit. It burns and stings, peaking as the skin thaws, then aches for a few hours. Fingertips, toes, soles and ears are sorest. Brief and unpleasant, not severe.

Before you leave

You go home with the liquid still on the skin.

Red, swollen and tender, sometimes blistering within the hour.

After your treatment

Cantharidin

Cryotherapy

First 24 hours

The spots look unchanged and you feel nothing.

Hours 4 to 24: A clear or cloudy blister rises over each treated bump.

Days 1 to 3: A clear or blood-filled blister is expected, not a sign anything went wrong.

Days 2–7

Not specified

Days 4 to 14: The blister dries into a dark crust with the growth on top, and lifts off on its own over one to two weeks.

Weeks 2–4

Weeks 1 to 2: The crust separates and takes the lesion with it, leaving pink, brown or pale new skin.

Weeks 2 to 8: New skin is pink and delicate.

Time to results

1–2 weeks per treatment

1–3 weeks

How long results last

Treated bumps don't return

Permanent for growths; warts may need repeats

Risks

A blister much larger than expected
Pain keeping a child awake
A ring of new bumps around a treated spot
A lasting dark or pale patch
Redness spreading beyond the spot

A pale mark that is not filling back in
A dark mark
Numbness or tingling
A raised or thickened scar
Hair loss in the treated patch
Still not healed after 4 weeks
The growth is back or never went

Cost

Per session

The answer depends on which product is used.

Cosmetic prices vary a lot and are usually quoted per lesion or per visit, cheaper per spot when several are done at once.

Insurance

The FDA-approved product is considerably more expensive, and what you pay depends on your insurance and how it is billed.

In the US, freezing warts and precancerous sun spots is billed as medical treatment, so you pay your copay or whatever the deductible has not covered.

Questions

Cantharidin

Cryotherapy

Individual Questions

Does it hurt?

Not when it is applied — nothing sharp touches the skin and no numbing is needed, which is why it suits young children. Hours later a blister forms and can be sore or itchy for a day or two.

How long do I leave it on?

Exactly as long as you are told. Contact times differ between the compounded solution and the FDA-approved product, and between molluscum and warts. Longer just makes a bigger, more painful blister.

Will it leave a scar?

Usually not. The skin splits above the rebuilding layer, so most spots heal without a scar. What lasts weeks to months is a flat brown, pink or pale mark — pigment, not scar tissue. Picking early is what turns a mark into a scar.

Why does my child keep getting new bumps?

Because the virus is still there. Cantharidin removes the bumps it is painted on, but molluscum keeps making new ones until the immune system recognizes it, which takes months. Hence repeating every few weeks.

Can it be used on the face?

No. Cantharidin is not applied to the face, eyelids, or mucous membranes such as the lips or genital skin, because a blister there is painful and risky. Ask what suits those locations.

Do we have to treat molluscum at all?

No. It clears on its own. Treatment is usually chosen when bumps are spreading quickly, itching, sore, in an awkward place, or affecting a child's activities.

Does freezing leave a white mark?

Often. Pigment cells die at milder cold than the growth, so most effective freezes take some color out. Some returns over months; a good part does not. The mark is usually a little wider than the spot and stands out far more on deeper skin tones — worth discussing before you agree.

Can a mole be frozen off?

No. Freezing destroys the tissue without a diagnosis, so a skin cancer can heal over at the surface while it keeps growing underneath. Anything pigmented, new or changing gets examined and sampled, and moles that need removing are cut out and sent to a laboratory. Same for at-home freezing and mole removal pens.

How much does it hurt?

A sharp burning sting for ten to thirty seconds during the freeze and the thaw, then an ache for a few hours. Fingers, toes, soles and ears are worst. Brief and genuinely unpleasant rather than severe, and ordinary painkillers are enough.

Is the blister normal, and should I pop it?

Normal, and it is how the treatment works — the skin separates and lifts the growth off with the blister roof. Leave it alone and cover it. If it is large, tense and painful, the clinic can drain it, which beats tearing the roof off yourself.

How many treatments will my wart need?

Usually several, every two to four weeks. Many clear over three to six treatments, some need more, and some never respond. Salicylic acid at home in between improves the odds. If nothing has changed after three or four sessions, ask about a different approach.

Are the drugstore freeze kits the same as what a doctor uses?

No. They use a propellant gas much warmer than liquid nitrogen and harder to aim, so they are weaker on thick and plantar warts. They can still blister and leave a pale mark. Not for the face, and never on a mole or an unexamined spot.

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