Ingrown Hairs on Underarms: Causes, Treatment & Prevention

That tender, itchy bump lurking in your armpit is almost certainly an ingrown hair. The underarm is one of the most common sites for them — and one of the most annoying, because you're tugging at the skin every time you reach for something. The good news is that ingrown hairs here are highly preventable once you understand what's actually causing them.

Why Underarms Are an Ingrown-Hair Hot Spot

The armpit checks every box for ingrown-hair trouble:

• Curved skin that moves constantly. The fold of skin shifts with every arm movement, which means freshly shaved hairs face shifting follicle angles all day long.
• Friction from clothing and deodorant. Antiperspirant residue and tight sleeves create a physical barrier that can trap emerging hairs at the surface.
• Coarser, multi-directional growth. Unlike leg hair, underarm hair grows in several different directions from the same patch of skin. A single shave stroke rarely cuts every hair at the same angle.
• Moisture and heat. Warm, damp environments encourage skin cells to build up faster, which can seal a follicle opening before the hair escapes.

According to the American Academy of Dermatology (AAD), ingrown hairs occur when a hair either grows back into the skin after shaving or fails to exit the follicle at all. Both types are common in the underarm.

What an Underarm Ingrown Hair Looks and Feels Like

• A raised, red or pink bump — sometimes resembling a pimple
• Tenderness or itching around the follicle
• A visible hair curled just beneath the skin surface
• In some cases, pus if the follicle becomes secondarily inflamed

An inflamed ingrown hair is not the same as an infected one. Mild redness and a small whitehead are normal. Spreading redness, significant warmth, or a bump that keeps growing after a week warrant a visit to a GP or dermatologist.

How to Treat an Existing Ingrown Hair

1. Warm Compress First

Hold a clean, warm damp cloth against the area for five to ten minutes. This softens the skin and dilates the follicle opening, which often lets the hair work its way out on its own. The NHS recommends this as the first-line approach before any physical intervention.

2. Gentle Exfoliation

After the warm compress, use a soft washcloth or a gentle chemical exfoliant (lactic acid or low-concentration salicylic acid) to loosen the dead skin cells capping the follicle. Avoid harsh scrubbing — the underarm skin is thin and already irritated.

3. Tease, Don't Dig

If the hair tip is visibly close to the surface, you can use a clean, sterilised fine-tip needle or pointed tweezer to gently lift — not pull — the looped end above the skin. Do not pluck it out entirely; the goal is to free the tip so the follicle can heal normally. If the hair is deep, leave it alone and continue warm compresses daily.

4. Hands Off

Squeezing or picking drives bacteria deeper and increases the chance of a genuine infection or post-inflammatory dark mark. It's harder to resist than it sounds, but worth it.

5. Skip Deodorant Temporarily

If the bump is in an active phase, give that spot a day or two free of antiperspirant — the aluminium compounds and fragrance can slow healing on broken skin.

How to Prevent Ingrown Hairs on Underarms

Prevention is where the real work happens. Most underarm ingrown hairs come back cycle after cycle because the underlying shaving habits haven't changed.

Use a Sharp, Single-Blade Razor

Multi-blade cartridge razors are designed to pull the hair slightly before cutting it, which leaves the tip fractionally below the skin surface — exactly where ingrowns start. A quality single-blade safety razor cuts at skin level without that sub-surface effect. The Freya starter kit is worth trying here: a weighted handle gives you control without pressing, and fresh blades every two to three shaves mean you're never dragging a dull edge.

Prep the Skin Properly

Shave after a warm shower, not before. Two minutes of warm water softens both the hair and the skin, making the cut cleaner and the follicle less likely to close over the hair as it regrows.

Shave With the Grain — or at Most Across It

For underarms this is tricky because growth goes in multiple directions. Take a moment to look (awkward but worth it) and identify the primary direction, then shave with it. One light pass is always better than two aggressive ones.

One Pass, Light Pressure

The armpit is not flat, so the temptation is to shave over the same spot repeatedly. Resist it. Multiple passes over the same skin strips the protective barrier and irritates follicles. A sharper blade used once is always better than a dull blade used three times.

Exfoliate Twice a Week Between Shaves

A gentle scrub or an exfoliating body wash with lactic acid twice a week keeps dead skin from piling up over follicle openings. Do this on non-shave days to avoid stacking irritants.

Apply an Unscented, Non-Comedogenic Moisturiser After Shaving

A light fragrance-free lotion or aloe vera gel immediately after shaving helps the skin barrier recover before deodorant goes on. Give it five minutes to absorb.

Let Skin Settle Before Applying Deodorant

Applying antiperspirant to freshly shaved skin — especially if you shaved dry or with a dull blade — dramatically increases irritation and follicle blockage. Moisturise first, wait, then apply.

Body-Area Context

Underarms are just one of several zones where ingrown hairs are common. If you're also managing them on your legs, bikini line, or elsewhere, the shaving technique principles carry across — our shaving by body area guide breaks down the adjustments zone by zone.

When to See a Doctor

See a GP or dermatologist if:

• The bump grows larger than a centimetre or is very painful
• You notice spreading redness, significant swelling, or red streaks
• You have recurring inflamed cysts in the same area (this may indicate hidradenitis suppurativa, a separate condition that requires medical management)
• You develop a fever alongside the bump

For the vast majority of people, consistent technique changes are enough to break the cycle entirely.

The Short Version

Underarm ingrown hairs are common, irritating, and almost always caused by a combination of dull blades, shaving against multi-directional growth, and deodorant friction. Treat existing ones with warmth and patience. Prevent future ones with a sharp single-blade razor, proper prep, grain-direction shaving, and light exfoliation between sessions. Most people who make these changes see a significant reduction within two to three shave cycles.

Frequently Asked Questions

Why do I keep getting ingrown hairs only in my underarms and not on my legs?

Underarm hair grows in multiple directions from the same patch of skin, and the folded skin shifts constantly with arm movement — two conditions that don't apply to legs. The friction from deodorant and clothing also traps emerging hairs in a way that bare leg skin doesn't.

Should I pop an ingrown hair bump in my armpit?

No. Squeezing drives bacteria deeper into the follicle, increasing the chance of a true infection and leaving a dark mark behind. Use a warm compress daily to encourage the hair to surface on its own, and only use a sterilised fine-point tweezer to gently lift the tip once it's visibly close to the surface.

How long does an underarm ingrown hair take to heal?

With warm compresses and no picking, most ingrown hairs resolve within one to two weeks. If a bump is still present, tender, or growing after two weeks, see a GP — it may have become infected and need treatment.

Is it better to shave underarms wet or dry?

Always wet. The AAD recommends shaving after a warm shower, which softens both hair and skin, reduces drag, and leaves the follicle opening cleaner after the cut. Dry shaving is a leading cause of follicle irritation and ingrown hairs.

Can switching to a safety razor really reduce underarm ingrown hairs?

For many people, yes. Multi-blade cartridge razors use a lift-and-cut mechanism that leaves the hair tip fractionally below skin level — a prime setup for ingrowns. A single-blade safety razor cuts at skin level without pulling, which reduces the sub-surface trim that starts the ingrown cycle.

Last updated: 2026-06-17