Warts: causes, symptoms, and therapy

Why warts develop, what types are there, what can be done against warts

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In a nutshell: what are warts?

Warts are benign skin growths. They occur preferentially on the hand, on the foot, on the face or in the genital area.

  • Causes: Most of the triggers are human papillomaviruses (HPV). There are many different types of HPV.
  • Symptoms: Warts often do not cause any symptoms. Genital warts can itch, plantar warts on the soles of the feet hurt when walking.
  • Diagnosis: The doctor usually makes the diagnosis based on the appearance of the wart.
  • Therapy: Warts are treated differently depending on their type, location and number.

Warts: the most common types

Vulgar warts

(Verrucae vulgares, common warts, barbed warts): This type is the most common. The skin growths are mainly found on the fingers, on the face and under the nail plate. They are the size of a pinhead to a pea and often look rough and scaly. The overgrown skin looks like a cauliflower. Brush warts (Verrucae filiformes) are reminiscent of small brushes in their shape.

Flat warts

(Verrucae planae juveniles, flat warts): They are flat and only a few millimeters in size. They are often found on the face as well as on the hands. Flat warts primarily affect children and adolescents and can occur in large numbers.

Warts on the soles of the feet

(Verrucae plantares): There are essentially two types, namely mosaic and plantar warts:

  • Mosaic warts occur in large numbers like beds, are very flat and are called mosaic warts because of their arrangement. They usually don't cause discomfort.
  • Plantar warts grow deep into the skin like the thorns of plants. They can cause considerable pain when walking. They usually have a very horny surface and are interspersed with dark dots.

Dellar warts

(Mollusca contagiosa): It is about the size of a pinhead, skin-colored to light red nodules with a characteristic dent in the middle. They contain a pulpy, whitish, virus-containing liquid. Dell warts occur preferentially on the face, neck, arms and legs. Children, in particular, who have dry skin and are prone to neurodermatitis, often develop warts because the skin's immune system is weakened. In contrast to the types of warts mentioned above, dellar warts are not caused by human papillomaviruses, but rather by a smallpox virus. You can find out more about warts in the Dell warts guide.

Genital warts

(Condylomata acuminata): This type of wart affects the genital and anal area. Unprotected sexual intercourse promotes transmission. The reddish to grayish-whitish nodules often form so-called wart beds. You can find more information on the subject in the guide to genital warts.

What are age warts?

Age warts (Verrucae seborrhoicae) occur more frequently from the age of 50 and appear mainly on the chest, back and face. Age warts sometimes look round, sometimes oval and can be the size of a lentil or a bean. They appear gray-brown to black and have a rugged surface. The nodules are not caused by viruses and are not contagious. The number of age warts increases with age. UV rays favor their appearance.

What are pedunculate warts?

Pedunculate warts are common. However, the name is misleading. Because the benign connective tissue growths do not even count among the warts. You can read more about this in the article stem warts.

© Mauritius Images GmbH / Photoresearchers


© Mauritius Images GmbH / Photoresearchers

Common warts (Verrucae vulgares) on fingers

© dermis.net

Plane warts (Verrucae planae juveniles) on the face

© iStock / sdominick

Plantar warts on the foot

© iStock / Jodi Jacobson

Dellar warts on the arm

© SciencePhotoLibrary / DrMarazzi

Age warts occur more frequently from the age of 50


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Warts are not nice to look at, but a closer look is important for a correct diagnosis. We have put together a few sample images for common types of warts.

Warts: causes and risk factors

Most warts are caused by the human papillomavirus (HPV). They can move from person to person, for example when shaking hands, or they can be transmitted through objects. For example, those who run around barefoot in the swimming pool or sauna can quickly catch the viruses.

If the viruses get on the skin or mucous membrane, they can penetrate the top layer of skin through tiny cracks or injuries. There they settle, infect individual cells and can thus proliferate the skin.

However, not everyone who carries HPV in cells in their epidermis will automatically develop warts.

The following factors favor the occurrence of viral warts:

  • Increased sweating, sweaty feet
  • A weakened immune system
  • A damaged skin, for example with neurodermatitis, or with small injuries to the nail fold by tugging on the skin
  • Smoke
  • diabetes

Children and teenagers are at an increased risk of developing warts. When your immune system comes into contact with the pathogens for the first time, the body cannot fight them sufficiently. There is initially no specific immune response against the virus, and the wart pathogens have an easy time of it.

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Warts: how does the doctor make the diagnosis?

Warts can usually be recognized by their typical appearance. Those affected should nevertheless go to the doctor, since the benign skin changes cannot always be clearly differentiated from skin cancer. Even people with previous illnesses such as diabetes, circulatory disorders or skin diseases should not experiment themselves.

The doctor examines the area of ​​skin carefully. In unclear cases he uses a reflected light microscope (dermatoscope), i.e. a magnifying glass with a built-in light source. If the growth is on the mucous membrane, the doctor can also dab the area with acetic acid. This can help make the diagnosis, as it turns the wart tissue white while the surrounding mucous membrane does not change its color.

If there are still doubts, the skin specialist will take a small tissue sample (biopsy) under local anesthesia and have it examined in the laboratory. In this way he can secure the diagnosis "wart" and also rule out a malignant change.

Therapy: what can help against warts?

Many warts go away on their own after a while. So sometimes it is enough to wait and see. However, the growths can be annoying or painful. They are also often contagious. Exception: Age warts and pedunculate warts are not contagious, they do not need to be treated.

The therapy depends on the type, location and number of warts and whether there are previous illnesses such as a diabetic foot. Genital warts require special therapy. You can read more about this in the guide to genital warts.

In principle, warts can be treated with special plasters, solutions or by freezing. The doctor may have to surgically remove the wart. Which therapy is suitable, which chances of success, advantages and disadvantages the treatment can have, should be discussed with the doctor individually. Not all therapy procedures are paid for by the health insurance company. Warts can reappear after therapy.

Salicylic acid or lactic acid for warts

Common warts, as well as flat warts and individually occurring plantar warts, can be treated with special plasters or solutions. The drugs contain substances such as salicylic acid or lactic acid - often in combination - which soften the keratinized skin. After a warm hand or foot bath, the softened horny layer can be removed. Tiny punctiform hemorrhages from the superficial blood vessels of the wart occur quite often. Normally, however, they are completely harmless. The plaster or the solution is then reapplied to soften the deeper parts of the wart. The entire procedure is repeated periodically until the wart is completely gone. Depending on how thick it is and how deep it extends into the skin, this can take several weeks to a few months.

Those who apply the tinctures at home should protect healthy skin from the aggressive agents. It is therefore best to cover the skin around the wart with petroleum jelly or another greasy ointment. Important: Thoroughly disinfect hands and used objects after each treatment so that the viruses are not spread to other parts of the body.

Cryotherapy: freezing the wart

Alternatively, the wart can be frozen with liquid nitrogen (cryotherapy). Flat warts, especially verrucae planae on the face, are dabbed by a doctor or a medical professional for a few seconds with a cotton ball soaked in liquid nitrogen. The wart tissue dies and the wart falls off on its own within a few days. For common warts (Verrucae vulgares) on the fingers, liquid nitrogen is usually sprayed on from a bottle. Since common warts are very persistent, freezing treatment is usually not enough. Regular freezing with liquid nitrogen by the doctor or a medical assistant can be a useful addition to self-treatment with plasters or solutions.

Icing in the doctor's office is done with liquid nitrogen at a temperature of minus 196 ° C. It is therefore considered to be more effective than self-treatment with less cold so-called freezing sprays from the pharmacy.

Further therapy options

If these methods do not completely heal the wart, the doctor may prescribe 5-fluorouracil as a tincture, among other things. However, 5-fluorouracil attacks the skin cells and should therefore be used with great care.

If warts appear in large numbers, form beds or grow heavily, they can be removed surgically or with a laser. In particular, deep-reaching plantar warts on the soles of the feet can cause painful wounds that take a few weeks to heal.

Some people try home remedies like apple cider vinegar, tea tree oil, or sticking duct tape on the affected area to get rid of the warts. There is no scientific evidence that these methods are effective or work better than acid therapy or cryotherapy.

How can you prevent warts?

This is how the risk of infection can be reduced:

  • Wear slippers in swimming pools, sports facilities, saunas and hotel rooms
  • Carefully dry the spaces between fingers and toes after bathing
  • Support the body's immune system: do not smoke, eat a balanced diet, exercise regularly in the fresh air
  • Apply lotion to dry skin regularly, especially on the hands. If there are small pieces of skin sticking out around the nail, these should be carefully cut off with sharp scissors. Plucking the scraps of skin leads to small wounds through which the viruses can easily penetrate the skin.

Anyone who has a wart should also ...

  • do not share towels or washcloths with family members
  • Wash towels and clothing that come into direct contact with the wart at a temperature of at least 60 degrees

Condoms can reduce the risk of developing genital warts, but they cannot be sure to prevent infection. You can read more about this in the guide to genital warts.

Vaccination against HPV

Vaccination against human papillomavirus can protect against infection with certain types of HPV. In this way, it can not only reduce the risk of cervical cancer and other types of cancer in the genital area, but also - depending on the vaccine - also prevent genital warts. The vaccination is currently recommended for boys and girls between the ages of 9 and 14 who have not yet had sexual intercourse. The doctor will advise on this. The vaccination has no preventive effect against other types of warts - such as vulgar warts, warts on the soles of the feet or flat warts.

Human papillomaviruses are considered a risk factor for developing cervical cancer and other cancers in the genital area. However, there are around 90 different types of HPV, of which experts consider types 16 and 18 to be primarily dangerous. Warts are predominantly caused by other types of HPV, which is why it is very unlikely that a wart will develop into a malignant tumor. There is only a certain risk for genital warts, as they also contain HPV types 16 and 18 in rare cases. You can read more about genital warts in the guide to genital warts.

Dr. med. Angela Unholzer

© W & B / private

Consulting expert

Dr. med. Angela Unholzer is a dermatologist with additional qualifications in allergology and dermatohistology. She completed her specialist training at the Dermatological University Clinic of the Ludwig Maximilians University in Munich and at the Clinic for Dermatology and Allergology at the Augsburg Clinic. At the latter clinic, she was senior physician in charge of the lighting department, the dermatological day clinic and the general dermatological outpatient department from 2006 to 2012. She then worked in a practice near Augsburg. She has had her own practice in Donauwörth since 2014.

Beth G Goldstein, Adam O Goldstein, Rachael Morris-Jones, "Cutaneous warts (common, plantar, and flat warts)", ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com (Accessed March 2018)

Beth G Goldstein, Adam O Goldstein, Patient education: Skin warts (Beyond the Basics), ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com (Retrieved March 2018)

Minor I: Dermatology. 8th edition, Stuttgart Georg Thieme Verlag 2016

Important NOTE:
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. It cannot replace medical advice. Please understand that we do not answer individual questions.

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