An ingrown hair is a strand of hair that curves back or grows sideways into the skin instead of rising up and out of the follicle. This triggers an inflammatory reaction, producing small, often painful bumps that can fill with pus and leave behind dark spots. Ingrown hairs are extremely common, especially in areas where hair is regularly shaved, tweezed, or waxed.
How Ingrown Hairs Form
Hair normally grows up through the follicle and out past the skin’s surface. When something disrupts that path, the hair can become trapped. There are two distinct ways this happens.
In the more common type, called extrafollicular penetration, the hair does make it out of the skin but then curls back down and pierces the surface nearby. This is especially likely with naturally curly or coiled hair, because the curved shaft follows its own arc right back into the skin. In the second type, transfollicular penetration, the hair never reaches the surface at all. Instead, it punctures through the wall of the follicle itself and grows directly into the surrounding tissue.
Either way, the body treats the re-entering hair like a foreign object. That sets off an inflammatory response: redness, swelling, and sometimes pus, all concentrated around a single hair.
What Ingrown Hairs Look and Feel Like
The hallmark sign is a small, raised bump in an area where hair has recently been removed. These bumps can take several forms:
- Firm, swollen papules that look like small pimples
- Pus-filled bumps that resemble whiteheads or blisters
- Dark spots where the bump heals but leaves behind pigmentation darker than the surrounding skin
- A visible hair loop where the tip of the hair has curved and re-entered the skin
Burning, stinging, and itching are all typical, and symptoms usually appear a day or two after shaving. In many cases, a single bump resolves on its own within a week or two. But if you shave again before it heals, or if the area is constantly irritated by clothing or friction, the cycle can repeat and worsen.
Why Some People Get Them More Often
The single biggest risk factor is hair texture. People with tightly coiled or very curly hair are significantly more prone to ingrown hairs because their hair naturally curves as it grows. This makes the extrafollicular pathway (hair curling back into the skin) far more likely. The condition is particularly common in Black men who shave their facial hair, where it’s formally known as pseudofolliculitis barbae.
Hair removal method matters too. Shaving cuts the hair at a sharp angle, creating a pointed tip that can more easily pierce skin on its way back. Shaving against the grain makes this worse by pulling the hair slightly before cutting it, so the remaining stub retracts below the skin surface. Tweezing and waxing can leave behind hair fragments beneath the surface or distort the follicle’s shape, both of which increase the chance of abnormal regrowth. Any body area that gets regularly shaved is vulnerable: the face, neck, legs, bikini line, and underarms.
Tight clothing adds another layer of risk. Fabrics that press against freshly shaved skin can push emerging hairs sideways or trap them against the surface. Dead skin cells can also block the follicle opening, forcing the hair to find an alternate path.
When Ingrown Hairs Become Infected
A simple ingrown hair is inflamed but not necessarily infected. The redness and swelling come from your immune system reacting to the trapped hair, not from bacteria. However, bacteria (commonly staph) can enter through the broken skin and cause a true infection called folliculitis.
Signs that an ingrown hair has become infected include increasing pain, a growing pocket of pus, warmth radiating from the bump, and whitish or bloody fluid leaking from the site. If the infection deepens, it can form a boil, which is a firm, painful lump with a pus-filled center. Multiple connected boils form a carbuncle, which can cause fever and fatigue.
Infected ingrown hairs that go untreated can lead to scarring. In some cases, chronic ingrown hairs produce permanent grooved scarring patterns. For people predisposed to abnormal scar tissue, repeated inflammation in the same area can trigger keloid formation, where thick, raised scars grow beyond the boundaries of the original wound. This is a recognized complication of chronic pseudofolliculitis barbae, particularly in Black men.
Prevention Strategies That Work
The most effective prevention method is also the simplest: stop removing hair entirely. When that’s not realistic, changing how you remove hair makes a significant difference.
If you shave, always shave in the direction of hair growth, not against it. Use a single-blade razor rather than multi-blade cartridges, which cut hair below the skin surface and increase the risk of the stub growing inward. Wet the skin with warm water first and use a lubricating shaving cream or gel. Rinse the blade after every stroke. Avoid pulling the skin taut while shaving, and don’t go over the same area multiple times.
Between shaves, gentle exfoliation helps prevent dead skin from sealing over the follicle opening. A soft washcloth or mild exfoliating scrub used a few times a week can keep the path clear for new hair growth. Wearing loose-fitting clothing over freshly shaved areas reduces friction that pushes hairs sideways.
For people who get frequent or severe ingrown hairs, laser hair removal offers a more lasting solution. The treatment damages the follicle to reduce hair growth over time. One clinical trial found that laser treatment combined with a prescription cream that slows hair growth achieved a median hair reduction of 99.5% over 16 weeks, compared to 85% with laser alone. Fewer hairs growing means fewer opportunities for ingrowth.
Treating Existing Ingrown Hairs
Most ingrown hairs resolve without treatment once you stop shaving the affected area and give the hair time to grow out naturally. Warm compresses applied for 10 to 15 minutes can soften the skin and help a trapped hair work its way to the surface. Resist the urge to dig at the bump with tweezers or a needle, which can introduce bacteria and worsen inflammation.
Over-the-counter products containing salicylic acid or glycolic acid can help by dissolving the layer of dead skin cells trapping the hair. These are available as creams, pads, or serums marketed for razor bumps or ingrown hair treatment.
For chronic cases, prescription options include topical retinoids, which speed up skin cell turnover to keep follicle openings clear, and topical antibiotics if bacterial infection is present. Prescription creams that slow hair regrowth can also help by thinning out the hair itself, making it less likely to pierce back through the skin. Steroid creams may be used short-term to reduce severe inflammation.
If a bump keeps growing, becomes increasingly painful, develops a fever, or starts leaking fluid, that signals a deeper infection that may need professional treatment. Persistent bumps that don’t respond to home care within a few weeks are also worth getting evaluated, especially to rule out other skin conditions that can look similar.