About ingrown hairs

An ingrown hair occurs when a hair curves back onto the skin and penetrates it.  The hair can then cause a brisk reaction in the skin, resulting in inflammation and possibly infection.  It usually appears as a skin-colored to red papule, sometimes with hyperpigmentation in chronic lesions.  Often, the hair can be seen centrally.  It is most common among those with curly hairs, and occurs with particular frequency in African American men, especially in the beard area and the occipital scalp.   The legs and bikini area in women are also frequently affected.  The condition can occur anywhere where the hair is shaved or broken off leaving a sharp tipped shaft.  This can occur after shaving or waxing.  Tight clothing has also been implicated.  An ingrown hair can also result from an occluded follicle, in which the growing hair is prevented from exiting.  Ingrown hairs can itch, or be angrily inflamed, red, and drain pus.

Razor bumps, or pseudofolliculitis barbae, is a form of ingrown hair and is addressed in a separate entry.

With what can an ingrown hair be confused?

The diagnosis is usually made clinically, but biopsy is sometimes necessary. Folliculitis, acne, keratosis pilaris, cysts, and abscesses are the most common differential diagnoses to consider.

How are ingrown hairs treated?

Ingrown hairs can be tweezed out.  Warm soaks are also helpful in dislodging the hairs.  Various acidic preparations and depilatories can be applied as well, which also my help prevent recurrence.  Eflornithine, which slows or prevents hair growth, can be used with similar purpose.  Topical retinoids, corticosteroids,and  topical and oral antibiotics can lead to improvement. Laser hair reduction for chronically affected areas may also be helpful, as can conventional electrolysis. Education on proper shaving technique is essential to reduce recurrence.  Untreated, the condition can result in scarring, keloids, prurigo nodularis, sinus tracts, and hyperpigmentation.

Tips for avoiding ingrown hairs

  • Wet hair for a while before shaving to soften it up and dull the hair.
  • Gently scrub the area with a soft brush or washcloth to help dislodge any stuck hairs.
  • Do not shave against the grain of the hair.
  • Do not shave too closely to the skin.
  • Leave a short stubble, if possible.
  • Allow the hair to grow out, if possible
  • Tweeze with a sterile tweezer and needle, following alcohol prep.  This is best left to a professional, as scarring can result if done inappropriately.

What is the prognosis for ingrown hairs?

Some ingrown hairs will resolve spontaneously.  Others if untreated may get infected, or lead to scarring and hyperpigmentation.