It’s often disturbing and somewhat alarming to discover a new skin growth. Skin tags and cutaneous warts -- meaning nongenital warts -- are among the most common causes of new skin growths. Aesthetically unpleasant and sometimes uncomfortable, skin tags and warts share some similarities. But there are also significant differences in cause, appearance, location, risk factors, typical course and treatment.
Warts, also known as verrucae, are caused by a superficial skin infection with the human papillomavirus (HPV). When HPV viruses infect superficial skin cells, they hijack their internal machinery and frequently stimulate increased cell growth that eventually leads to the appearance of warts. There are more than 150 known types of HPV, and the various types tend to favor specific body sites. Warts are highly contagious.
The cause of skin tags, also known as acrochordons, is poorly understood. However, as they tend to occur at sites where skin surfaces rub together, irritation caused by skin friction might contribute to the development of skin tags. Hormonal influences might also be a factor. As they are not caused by an infection, skin tags are not contagious.
Appearance and Texture
Skin tags are small, flesh-colored or brown growths that hang from the skin surface. These noncancerous growths typically have a thin stalk that connects them to the skin surface. Skin tags have a soft texture and most are smaller than one-quarter inch, though they sometimes grow larger. Multiple skin tags commonly develop at a given site, although solitary growths also occur.
Warts appear differently, based on the type of HPV responsible and the site on the body. Common warts typically appear as dome-shaped growths with a rough surface that might contain tiny black specks. These firm growths usually range from one-quarter to three-eighths of an inch in size, and are most commonly slightly gray or brown in color. Plantar warts, which occur on the soles of the feet, resemble common warts but with a smoother surface due to friction at this site. Flat warts are only slightly raised from the skin surface. They are usually smooth, resemble small pimples and tend to appear in crops. Flat warts are typically pink, light brown or slightly yellow. Filiform warts arise from the skin surface off a narrow base and have tiny finger-like projections on the surface.
Skin tags most commonly occur at sites that experience friction, including the armpits, neck and groin area. They also commonly develop on the eyelids, and beneath the breasts in women. Among people carrying excess body weight, skin tags often occur in skin folds of the belly or back.
Warts can develop on any skin surface, but different types tend to occur in specific sites. Common warts most frequently occur on the fingers, hands, arms and legs. Plantar warts develop on the soles of the feet and sometimes on the ankles. The face is the most common site for filiform and flat warts. Flat warts also frequently develop on the legs and arms.
Age and Risk Factors
Skin tags occur almost exclusively in adults, and the likelihood of developing increases with advancing age. Skin tags may first appear in women during pregnancy. Caucasians, people who are overweight, and those who have diabetes or metabolic syndrome are at increased risk for developing skin tags.
Where skin tags occur primarily in middle-aged and older adults, warts most frequently occur in children, teens and young adults. The main reason is the development of immunity to many of the common types of HPV as a person ages. However, warts can develop in adults if exposed to a type of HPV for which they possess no immunity. Risk factors for warts include:
-- use of communal showers
-- a weakened immune system
-- regularly handling raw meat
-- chronic skin conditions, such as atopic dermatitis
As skin tags are noncancerous and typically cause no symptoms, medical treatment is not necessary. However, people often opt to for removal if they are located on the face or an area where they regularly catch on clothing or jewelry. Most skin tags can be simply cut off in the doctor's office. Larger skin tags are often removed using a freezing technique or electrodessication -- destruction with a short burst of electrical current.
Most skin warts eventually go away on their own. However, many people opt for treatment to speed their disappearance because they are contagious, often spread, might be uncomfortable and are frequently unsightly. The choice of wart treatment depends on various factors, including age, location, and the size and type of wart. Over-the-counter treatments available for common and plantar warts include salicylic acid liquid or patches, and freezing sprays or liquids. These products should not be used on the face. Other treatment options available from a doctor include in-office surgical removal or destructive therapies, such as topical medicines, freezing and electrodessication.
Next Steps and Precautions
Neither skin tags nor cutaneous warts pose a serious health risk. However, other potentially serious skin growths -- such as skin cancers -- might appear similar. Therefore, see your doctor if you notice a new skin growth and are not sure what it is. This is particularly important if the growth exhibits any warning signs or symptoms, including:
-- rapid growth or size larger than a pencil eraser
-- variable coloration
-- irregular border
-- asymmetrical shape
-- ulceration, itchiness or bleeding
It is usually safe to try an over-the-counter remedy for a plantar or common wart. However, see your doctor if the treatment is not working, you have a facial wart or flat warts, or the lesion is large or painful.
Reviewed and revised by: Tina M. St. John, M.D.