Ingrown hairs: why they happen, how to treat them, and how to prevent them

Ingrown hairs happen when a hair curls back or grows sideways into the skin instead of growing out, causing a small red or dark bump that can itch or sting. They are most common after shaving or waxing, especially on the legs, bikini line and underarms, and in curly or coarse hair. Most clear on their own, and a few changes to how you remove hair prevent most of them. Here is why they happen, how to treat a bump safely, and how to stop them coming back.

General information, not medical advice. See a doctor if a bump becomes very painful, hot or swollen, or keeps coming back.

Why do ingrown hairs happen?

• Shaving leaves hair with a sharp, angled tip that can pierce the skin as it grows.
• Curly or coarse hair naturally bends back toward the skin.
• Waxing and tweezing can damage follicles and change how hair grows back.
• Dead skin can trap hairs under the surface.
• Tight clothing rubs freshly shaved skin.

Ingrown hairs, razor bumps or folliculitis?

They often look alike. Razor bumps are ingrown hairs after shaving. When a damaged follicle becomes infected, it is called folliculitis: the American Academy of Dermatology describes it as a common infection of the hair follicles that looks like a sudden breakout of acne-like spots, sometimes with a red ring, and lists shaving and waxing among the common causes.

How to treat an ingrown hair

1. Leave it alone if you can; most work their way out within days.
2. Apply a warm compress. For folliculitis, the AAD suggests a warm compress at least 3 to 4 times a day for 15 to 20 minutes.
3. Exfoliate gently around the area with a soft washcloth to free the hair.
4. Do not dig or squeeze, which can cause infection, scarring or dark marks.
5. If the hair loop is visible at the surface, you can lift it gently with a sterile needle or tweezers, without pulling it out.
6. Pause hair removal in that area: the AAD suggests stopping shaving, plucking or waxing for about 30 days if they caused folliculitis.

How to prevent ingrown hairs when shaving

The AAD's razor bump prevention tips work for ingrown hairs too:

• Shave when hair is soft, at the end of a shower or after a warm, damp washcloth.
• Use a moisturizing shaving cream and a non-comedogenic cleanser beforehand.
• Shave in the direction the hair grows.
• Rinse with warm water, then press a cool, damp washcloth on the skin.
• Replace disposable razors every 5 to 7 shaves and store them dry.
• Shave more often, every day or every 2 to 3 days, so hair has less time to curve back.

Other ways to prevent ingrown hairs

Exfoliating and moisturizing

• Exfoliate a few times a week with a soft washcloth or a gentle chemical exfoliant such as salicylic or glycolic acid, not right after shaving.
• Moisturize daily so skin stays soft and hairs grow out more easily.
• Wear loose clothing after shaving or waxing, especially in heat.

Ingrown hairs on the bikini line

The bikini line is especially prone because the hair is coarse and clothing rubs the area. Trimming instead of shaving close, shaving with the grain, and loose cotton underwear all help. Never try to dig out a deep bump there; see a doctor if it is painful or infected.

Dark marks after ingrown hairs

Ingrown hairs can leave dark spots, especially on deeper skin tones. They fade slowly; gentle exfoliation, daily sunscreen on exposed areas and ingredients such as azelaic acid can help. For dotted dark pores on the legs, see strawberry legs.

When to see a doctor

See a doctor or dermatologist if a bump becomes very painful, swollen, warm or filled with pus, if you have a fever, or if ingrown hairs keep coming back. The AAD notes that some people need an antibiotic, and that untreated razor bumps can cause lasting scars.

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