An ingrown hair happens when a hair curls back or grows sideways into the skin instead of rising up and out of the follicle. The tip of the hair pierces the surrounding skin, and your body treats it like a foreign invader, triggering inflammation, redness, and often a painful bump. The process involves a combination of how hair naturally grows, what’s happening at the surface of your skin, and external factors like shaving or tight clothing.
What Happens Inside the Follicle
Every hair on your body grows from a small tunnel in the skin called a follicle. Normally, a hair pushes straight up through this tunnel and exits cleanly at the surface. An ingrown hair breaks that pattern in one of two ways: either the hair never makes it out of the follicle and curls back on itself beneath the skin, or it exits the surface, curves, and re-enters the skin nearby.
A protein called keratin plays a central role. Your skin constantly produces keratin as part of its normal cycle of building and shedding cells. When dead skin cells and keratin clump together, they can form a plug at the opening of the follicle. This blocks the hair’s exit path. With nowhere to go, the growing hair bends sideways or downward, embedding itself in the tissue around the follicle. The result is a small, inflamed bump that can look like a pimple and sometimes contains a visible loop of hair beneath the surface.
Why Curly Hair Is More Prone
Hair texture is the single biggest factor in how often ingrown hairs occur. People with very curly or coarse hair are significantly more likely to develop them. The reason is mechanical: a tightly coiled hair has a natural curve that directs its growth back toward the skin rather than away from it. Once the sharp tip contacts the skin surface, it can pierce through and continue growing beneath.
This is why ingrown hairs are especially common in the beard area for men with curly hair, a condition formally called pseudofolliculitis barbae. It also explains why ingrown hairs tend to cluster in areas where hair is naturally coarser, like the bikini line, underarms, and legs. Straight, fine hair can still become ingrown, but it happens far less frequently because the growth angle carries the hair away from the skin.
How Shaving and Grooming Contribute
Shaving is the most common trigger for ingrown hairs, and the reason comes down to what happens to the hair tip. When you cut a hair with a razor, you create a sharp, angled edge. That freshly cut tip is better at piercing skin than a naturally tapered hair would be. Shaving against the grain makes this worse because it pulls the hair slightly out of the follicle before cutting it, allowing the remaining stub to retract below the skin surface. From there, it can easily grow into the follicle wall instead of upward.
Multi-blade razors compound the problem. The first blade lifts the hair while subsequent blades cut it progressively shorter, often below skin level. Dermatologists recommend using a single-blade razor and shaving in the direction your hair grows naturally to minimize the risk. Other practical steps that help: wetting the skin and hair thoroughly with warm water before shaving, using a shaving gel or cream to reduce friction, rinsing the blade after every stroke, and replacing the blade frequently so it stays sharp enough to cut cleanly without tugging.
Waxing and tweezing can also cause ingrown hairs. When you pull a hair out by the root, the new hair growing in its place has to navigate the entire length of the follicle. If the follicle opening is partially blocked by dead skin, or if the new hair grows at a slightly different angle, it may become trapped.
The Role of Friction and Tight Clothing
Pressure against the skin from tight clothing can physically push emerging hairs back into the follicle or flatten them against the surface until they re-enter. This is why ingrown hairs are common along waistbands, bra lines, and the inner thighs. The constant rubbing also irritates the skin and promotes the buildup of dead cells over the follicle opening, compounding the blockage. Switching to looser fabrics in problem areas, especially right after shaving or waxing, can make a noticeable difference.
What an Ingrown Hair Looks and Feels Like
Most ingrown hairs appear as small, round bumps that look similar to pimples. They’re often red or darker than the surrounding skin and can be tender or itchy. You may be able to see the hair curled beneath the surface. Some ingrown hairs fill with pus, which makes them look even more like acne. In many cases, they resolve on their own within a week or two as the skin sheds and the hair eventually breaks free.
Picking at or squeezing an ingrown hair often makes things worse. It introduces bacteria, damages the surrounding skin, and can push the hair deeper. If you leave it alone, your body’s normal skin turnover will usually clear the obstruction. Gently exfoliating the area with a washcloth or a mild scrub can speed up the process by removing the dead skin cells trapping the hair.
When Ingrown Hairs Get Infected
An ingrown hair creates a small wound beneath the skin, and bacteria can colonize that wound. A superficial infection of the follicle (folliculitis) causes increased redness, more pus, and a warm sensation around the bump. This usually clears up on its own or with a warm compress.
Rarely, the infection spreads into the deeper layers of skin. Signs of this include spreading redness beyond the original bump, increasing warmth and swelling, skin that becomes progressively more tender, and feeling unwell. These are signs the infection has moved past the follicle and into surrounding tissue, which requires medical treatment. The risk is higher if you’ve been repeatedly picking at the bump or if your immune system is compromised.
Long-Term Solutions for Chronic Ingrown Hairs
For people who get ingrown hairs repeatedly, especially in the beard area, adjusting shaving habits only goes so far. Chemical exfoliants containing salicylic acid or glycolic acid can help keep follicle openings clear by dissolving the dead skin and keratin that cause plugs. Applying these regularly to problem areas reduces the frequency of new ingrown hairs.
Laser hair removal is often recommended as a more permanent solution for chronic cases. It works by reducing the total number of hairs growing in the treated area. A study of 50 patients treated with laser hair removal for chronic beard ingrown hairs found that 70% had at least a 75% reduction in ingrown hair lesions after completing treatment, and 88% were satisfied with the results. After treatment, 96% of participants were able to resume shaving comfortably.
The results do fade, though. In that same study, ingrown hairs recurred in 84% of participants, with more than half experiencing recurrence within six months of their last session. Many patients also noticed patchy regrowth initially, which became more even over time. The takeaway is that laser hair removal works well but typically requires maintenance sessions every few months to keep ingrown hairs from returning. A standard course involves four to six sessions spaced four to eight weeks apart, with touch-ups recommended within six months of the last treatment.