Alerts and Notices
SynopsisAn ingrown hair occurs when the distal tip of a hair shaft penetrates and grows back into the interfollicular skin following prior removal via shaving, tweezing, or waxing. The inflammatory response toward the entrapped hair results in the formation of firm perifollicular papules or pustules that can be tender or pruritic.
The condition can affect anyone who engages in hair removal practices, but it is more common in people with tightly curled or coarse hair, which has a higher tendency to curve back toward and penetrate the interfollicular skin. It commonly affects African American men following facial hair removal in the beard distribution, where pseudofolliculitis barbae ensues.
L73.1 – Pseudofolliculitis barbae
9115004 – Pili incarnati
Differential Diagnosis & Pitfalls
- Bacterial folliculitis – Typically has more of an acute presentation. Positive cultures can be used to diagnose this condition, as bacterial cultures are typically negative in ingrown hairs.
- Miliaria rubra / pustulosa – Pustules would not be perifollicular in miliaria.
- Traumatic folliculitis – Transient inflammation secondary to irritation from shaving can result in traumatic folliculitis. However, this condition is more acute, with resolution of lesions within a few days.
- Acne vulgaris
- Other forms of folliculitis – viral (herpes, zoster), fungal (Majocchi granuloma, Pityrosporum folliculitis), parasitic (Demodex folliculitis), inflammatory (eosinophilic folliculitis)
- Inflamed or infected epidermal inclusion cyst
- Hidradenitis suppurativa