By Cynthia Bailey MD. This page was updated on Sun, Dec 15, 2019
What is an ingrown hair?
Hairs grow in a hair follicle, which is a small canal in the skin lined by skin cells. Typically, hairs make it to the opening of the hair follicle without difficulty. If a hair fails to exit this canal to the skin surface it can track along the dead cell and epidermal cell layer in a canal. You see that as a dark line or coil. Hair can also pierce the follicle lining or epidermis and enter a portion of the skin called the dermis. Hair that has exited the follicle can also turn back around and grow in the epidermis, or pierce the skin, entering the dermis. Hairs that inter the dermis cause inflammation
What are the symptoms of an ingrown hair?
If the hair is tracking in the epidermis or under the stratum corneum dead cell layer then you see it as a dark line or coiled hair. There may be a bump but the ingrown hair is usually asymptomatic.
If the hair enters the dermis then there is inflammation. That's because the body does not like hair in the dermal layer layer of the skin. It sees the hair as foreign and tries to destroy the shaft of hair. There is redness, tenderness, swelling and pus, just like with a splinter.
Why do ingrown hairs happen?
The main problem that starts both of these types of ingrown hair is that either dead cells cover the skin opening of the follicle, or a hair coils back and enters the skin.
Normally hairs grow in the canal and exit freely to the skin surface where they can be shaved, cut, or allowed to grow. Each hair follicle grows for a predetermined number of months or years, then rests. When the hair follicle resumes producing a shaft of hair, the old hair strand is shed and a new hair starts growing from the bottom of the follicle. Typically, the new hair follows the follicle and exits at the top. Sometimes it doesn't work though and the hair in grows.
In addition, hairs shaved sharply at the skin surface can retract back into the hair follicle and, especially if curly, may pierce into the hair canal lining, instead of making a straight exit out of the opening of the follicle. Shaved hair has a nice point for piercing the skin. Tweezed, waxed and epilated hairs may also in grow.
Rubbing and friction can cause hairs to coil and in grow too. Curly hairs are particularly prone to ingrowing.
Why do ingrown hairs leave scars and brown marks?
The redness and inflammation from an ingrown hair can leave a temporary or permanent mark when it heals. If you have dark skin, or if you are in the sun and your skin produces melanin (a tan), that melanin can drop into the deeper skin layer (the dermis) where it can stay for a long time.
What is the best way to prevent ingrown hairs?
10 tips to help prevent ingrown hairs - follow these steps:
- Keep the dead cell layer exfoliated to help hairs exit the follicle. Do this exfoliation regularly using rough scrubs, cloths, or sponges with your skin cleanser to massage your skin. Use a gentle circular motion to help loosen and tease out any early coiling hairs.
- Use keratolytic skin care product ingredients that loosen dead cells to prevent build-up of the dead cell layer called the stratum corneum. Good keratolytic ingredients include benzoyl peroxide, salicylic acid, glycolic acid, and retinoids (like retinol). My Ultra-Fast Body Smoothing Triple Action Kit is excellent for ingrown hairs on the body. Foaming Benzoyl Peroxide Acne Treatment Cleanser and Foaming Acne Treatment Cleanser with salicylic acid and glycolic acid are excellent choices for the face. An Exfoliating Facial Sponge is a useful exfoliating step to use with your facial cleanser. Bamboo and Clay Exfoliating Scrub is another great exfoliating option to help keep hair follicles open. Retinol Night Cream or Glycolic Acid Face Cream are highly effective keratolytic creams to help prevent ingrown hairs. Glycolic acid can't be used after shaving though because it stings! The Retinol Cream will also help heal ingrown hair scars.
- Prevent friction of areas prone to ingrown hairs such as the groin by wearing loose clothing.
- Wash and rinse your skin well before shaving to remove skin bacteria.
- Shave with a clean and sharp razor, and rinse the razor between each stroke.
- Shave in the direction of the hair.
- Don't pull the skin tight when you shave.
- Avoid close shaves and consider leaving a stubble of hair to prevent hairs from resting below the opening level of the hair follicles.
- Rinse skin with cool water after shaving to reduce skin inflammation from shaving.
- Apply a soothing moisturizer after shaving to minimize skin irritation and keep skin soft and pliable.
What is the best way to heal ingrown hairs and prevent scars?
Be sure the ingrown hair lesion does not become infected. Rubbing alcohol or hydrogen peroxide may help. Topical antibiotics such as bacitracin may help too. You may need to seek medical attention for prescription medicines.
If possible, use clean tweezers and pull the hair out of the follicle if it is readily visible. Prep the skin with rubbing alcohol first and disinfect the tweezers with rubbing alcohol too. Do not damage the skin. Again, you may need medical attention to do this aseptically.
When ingrown hairs occur, protect the skin from the sun to prevent hyperpigmentation (called post inflammatory hyperpigmentation). I have listed non-irritating mineral zinc oxide sunscreens on the page below. These give the best broad spectrum sun protection to help prevent tanning of skin prone to ingrown hairs.