Medical Terminology for Ingrown Hair
The medical term for an ingrown hair is pseudofolliculitis (or more specifically, pseudofolliculitis barbae when it occurs in the beard area). 1, 2
Definition and Pathophysiology
Pseudofolliculitis is a foreign body inflammatory reaction that develops when a hair grows back into the skin rather than emerging from the follicle. 1, 2 This condition occurs through two distinct mechanisms:
- Transfollicular penetration: The curved hair re-enters the follicle wall before exiting the skin surface 1
- Extrafollicular penetration: The hair exits normally but curves back to pierce the skin adjacent to the follicle 1
The inflammatory response results from the body recognizing the ingrown hair as a foreign object, leading to papules, pustules, and potential scarring. 3
Clinical Presentation
Pseudofolliculitis presents as:
- Inflammatory papules and pustules at sites of hair removal 1, 4
- Chronic inflammation surrounding the ingrown hair shaft 4
- Potential for hyperpigmentation and keloid formation in severe cases 1
- Most commonly affects individuals with curly or coarse hair, particularly men of African descent 4, 5
Risk Factors
The condition is strongly associated with:
- Curly or wavy hair texture, which increases the likelihood of hair re-entry into skin 2, 4
- Genetic predisposition, including a single-nucleotide substitution in the keratin 75 gene 4
- Shaving practices, particularly close shaving that creates sharp hair tips 2, 5
- Body areas with coarse, abundant hair subject to traumatic removal 4
Common Terminology Variants
- "Razor bumps" - colloquial term for pseudofolliculitis barbae 5
- "Ingrown hairs" - lay terminology for the same condition 5
- Pseudofolliculitis barbae (PFB) - specifically refers to the beard/facial area 3
- Pseudofolliculitis cutis (PFC) - broader term encompassing all body sites 4
Important Clinical Distinction
Do not confuse pseudofolliculitis with folliculitis, which is an actual infection of the hair follicle typically caused by bacteria. 6 Folliculitis presents as papules and pustules but represents true infection rather than a sterile foreign body reaction to ingrown hair. 6