Warts (Verruca): Types, Wart vs. Corn, and How They're Treated

This is an English adaptation of a clinical article Dr. SangYoul Yun — board-certified dermatologist and Medical Director of Delight Dermatology in Gangnam, Seoul — originally published in Korean. Read the Korean original on Naver. It has been restructured and translated for international readers.

Do you have stubborn warts on your face, neck, hands or feet? Today I want to explain why warts appear, how they present, and how they're treated.

What is a wart (verruca)?

A wart is a benign growth of the skin or mucosa caused by human papillomavirus (HPV) infection. Warts most often appear on exposed areas — the hands, feet, legs and face — and, through sexual contact, on the genitals. Because they're driven by HPV, the clinical appearance varies with the HPV genotype involved.

Wart type by HPV genotype

Type	Associated HPV types
Common wart	HPV 2, 4, 27, 29
Flat wart (verruca plana)	HPV 3, 10
Palmoplantar wart (hands/soles)	HPV 1

How each type looks

Common warts

The most common type — rough, raised lesions on the backs of the hands and around the nails. They occur mostly between ages 5 and 20, with about 15% appearing in people over 35.

Flat warts (verruca plana)

These have a flat, even surface — as if sliced by a knife — sitting slightly raised above normal skin, typically 2–4 mm and appearing in numbers. They're usually round and skin-colored, though they can merge into irregular shapes. They favor the forehead, chin, nose, the area around the mouth and the backs of the hands, and occur in adults as well as children and teenagers. When flat warts appear on the face, neck or body they can spread quickly — sometimes into the hundreds, so early treatment matters. My own view is that treatment for treatment for non-spreading lesions (and things like sebaceous hyperplasia) can be deferred according to the patient's own needs, but for flat warts I recommend treating early — because many people who put it off end up with dozens or hundreds of lesions.

Palmoplantar warts (hands and soles)

Under the pressure of body weight, these are pushed inward into the skin surface. Left this way, a thick callus often forms around them.

Wart or corn? How to tell them apart

It can be hard to distinguish a plantar wart from a corn. A few pointers:

• A corn hurts more when pressed from directly above than from the side — because of the hard yellow core in the center.
• A wart, when pared down, shows tiny black "sesame-seed" dots — these are ingrown capillaries.
• Multiple lesions raise the likelihood of warts.

Treatment

Many people seek treatment for cosmetic reasons on the face, but warts on the palms and soles are painful and spread quickly, so treatment is definitely needed there.

1. Cryotherapy

Liquid nitrogen (−195 °C) is applied with a cotton swab or cryo-spray, with treatment repeated over several visits — generally around 5–10 sessions at two-week intervals, though more or fewer sessions may be needed depending on severity. A blister may form afterward; if it isn't uncomfortable it resorbs on its own, and if it swells significantly it can be dealt with appropriately.

2. Bleomycin injection

This works by necrosing the wart tissue to remove the lesion. Because it can cause side effects such as a blood blister, cryotherapy is usually tried first, with bleomycin reserved for lesions that don't respond.

3. Laser treatment

For lesions that don't respond to earlier treatments, a CO₂ laser can burn away and remove the wart. In our clinic, precise laser lesion removal is part of our spot / lesion removal care.

There is also immunotherapy (DPCP), which applies an agent that provokes an immune response — but relatively few clinics use it in practice.

Many people simply live with warts, assuming they'll disappear on their own. But because a wart is a viral HPV infection, leaving it untreated can allow it to spread by contact and grow in size and number. Getting appropriate treatment early is important.

Medical disclaimer. This article is general information and does not replace individual consultation. A wart is a viral skin condition; accurate diagnosis (including telling a wart from a corn or other lesion) and the choice of treatment should be decided after an in-person examination by a dermatologist. Injectable treatments such as bleomycin are performed under a physician's care.