Warts are small, rough-textured skin growths caused by the human papillomavirus (HPV). They typically feel like a firm bump with a grainy surface, range from 1 millimeter to a couple of centimeters across, and often have tiny black dots visible on the surface. Those black dots are clotted blood vessels, not seeds, and they’re one of the most reliable visual clues that a growth is a wart rather than something else.
What Common Warts Look and Feel Like
Common warts most often appear on your hands and fingers. They feel like rough, raised bumps with a texture similar to cauliflower or sandpaper. The color is usually skin-toned, grayish, or slightly yellowish-brown. When you look closely, you may notice those characteristic black dots scattered across the surface, each one a tiny blood vessel the virus has recruited to feed the growth.
Common warts are usually painless unless they’re in a spot that gets bumped or pressed frequently. They tend to have well-defined, rounded borders and a dome shape, though clusters of warts can merge into irregular patches. A single wart can spread to nearby skin through direct contact or scratching, so it’s not unusual for one wart to become several over weeks or months.
Plantar Warts vs. Calluses
Warts on the bottom of your foot (plantar warts) are easy to confuse with calluses because both create thickened patches of skin. Two simple tests help you tell the difference.
First, look at the skin lines. Your feet have fingerprint-like ridges across the sole. On a callus, those ridges continue straight through the thickened skin, uninterrupted. On a plantar wart, the ridges go around the growth, not across it, because the virus has disrupted the normal skin structure underneath.
Second, try the squeeze test. Press your thumb straight down on the center of the spot, then pinch it from the sides. If direct downward pressure hurts more, it’s likely a callus: you’re compressing layers of dead skin against sensitive tissue below. If squeezing from the sides hurts more, it’s likely a plantar wart. Warts grow into the skin and develop their own network of blood vessels and nerve endings, which get compressed when you pinch laterally. Plantar warts may also show the same black dots you see in common warts, though they can be harder to spot through the thickened sole skin.
Flat Warts and Filiform Warts
Not all warts look like rough bumps. Flat warts are smooth, slightly raised, and only a few millimeters across, often the same color as your skin or slightly pinkish-brown. They tend to appear in large numbers, sometimes dozens at a time, on the face, forehead, or legs. Shaving can spread them along a line, which is why clusters of flat warts sometimes follow a razor’s path.
Filiform warts look completely different. They grow outward from the skin as narrow, finger-like projections, almost like tiny skin tags with a pointed tip. They favor the face, especially around the eyelids, lips, nose, and neck. Filiform warts are painless but cosmetically noticeable because of their unusual shape and location.
Warts Around and Under the Nails
Periungual warts grow around the edges of fingernails or toenails and can extend underneath the nail plate. They start as small, rough bumps near the cuticle but can gradually distort the nail itself as they grow, causing ridges, splitting, or lifting of the nail. These warts sometimes create fissures (small cracks) in the surrounding skin that can be painful and prone to secondary infection. Because they involve the nail bed, periungual warts are among the most stubborn types to treat and are worth having a dermatologist evaluate early, before they cause permanent nail damage.
Genital Warts
Genital warts are caused by different strains of HPV than the ones responsible for hand or foot warts. They appear as flat, raised, or stalk-like growths on the genital and anal skin, including the vaginal opening, the penile shaft, the foreskin, perineum, scrotum, and perianal area. They can also develop internally on the cervix, vagina, urethra, or inside the anal canal, where you wouldn’t see them yourself. Genital warts are often skin-colored or slightly darker and may appear singly or in clusters. They’re typically painless, though some people notice itching. Because they’re sexually transmitted and certain HPV strains carry cancer risk, any new growth in the genital area is worth getting evaluated professionally rather than trying to self-diagnose.
Growths That Look Like Warts but Aren’t
Several other skin conditions mimic warts closely enough to cause confusion.
Seborrheic keratoses are waxy, brownish patches that look like they’ve been glued or “stuck on” the skin’s surface. They’re extremely common in people over 50 (about 75% of people have at least one by age 70) and are completely harmless. Unlike warts, they don’t have black dots, feel waxy rather than rough, and don’t spread through contact.
Skin cancers can also resemble warts in early stages. A few features should prompt you to get a growth checked rather than assuming it’s a wart:
- Asymmetry: one half of the growth doesn’t match the other
- Irregular borders: ragged, blurred, or uneven edges instead of a clean outline
- Multiple colors: shades of tan, brown, black, blue, white, or red within a single spot, rather than a uniform tone
- Rapid changes: a growth that’s quickly getting larger, changing color, itching, or bleeding
- Won’t heal: a sore or scaly patch that crusts, bleeds, and never fully resolves
Squamous cell carcinoma, for instance, can appear as a firm reddish nodule or a scaly growth that bleeds and crusts, which is easy to mistake for an irritated wart. The key difference is that warts tend to be stable (or slowly growing), uniformly colored, and predictable in texture. Any growth that breaks those rules deserves a closer look from a dermatologist.
Confirming What You’re Dealing With
Most warts can be identified at home using the visual and tactile clues described above: a rough, well-defined bump with black dots, disrupted skin lines, and lateral squeeze tenderness on the foot. If the growth matches those patterns and you’re otherwise healthy, you can be reasonably confident it’s a wart.
A dermatologist can confirm the diagnosis in seconds by examining the surface under magnification, and in ambiguous cases, by shaving off a small sample for microscopic analysis. This is especially worthwhile for growths that are unusually dark, irregularly shaped, bleeding without trauma, or located in areas where you can’t see them well yourself. It’s also worth seeking professional evaluation for any wart that persists for more than two years without responding to over-the-counter treatment, since long-standing growths occasionally turn out to be something other than a simple wart.