When two or more hairs emerge from a single skin opening, it’s a known biological phenomenon. This article explores why this occurs and when it warrants closer attention.
The Basics of Hair Follicles
Hair follicles are tunnel-shaped structures extending from the epidermis into the deeper dermis, and sometimes into the subcutaneous tissue. At the base of each follicle lies the hair bulb, which contains the dermal papilla and hair matrix cells. The dermal papilla provides nutrients, while the hair matrix cells rapidly divide to form the hair shaft.
Hair grows in a cycle with distinct phases. The anagen phase is the active growth period, where hair cells divide and the hair lengthens. This is followed by the catagen phase, a brief transitional stage, and then the telogen phase, a resting period where hair rests before shedding during the exogen phase. Normally, each follicle produces a single hair.
Why Multiple Hairs Emerge
Pili multigemini is the medical term for multiple hairs growing from a single opening, where one follicle produces more than one hair shaft. This is most commonly attributed to structural variations, such as a partially divided hair matrix or multiple dermal papillae within one follicular unit. This variation often has a genetic component and can run in families.
Trauma or inflammation can contribute to this pattern. Skin conditions like folliculitis, an inflammation or infection of the hair follicle, can alter the normal hair growth cycle and lead to multiple hairs emerging from a compromised follicle. Physical irritation, such as repeated shaving or waxing, can influence the follicle’s behavior.
Hormones influence hair growth and follicle activity. Hormones such as androgens, estrogen, progesterone, and thyroid hormones interact with hair follicles, affecting their growth cycle. Though less direct than structural variations, hormonal imbalances can influence multiple hair emergence.
When to Be Concerned
Multiple hairs from one follicle are often a normal, harmless variation. It typically doesn’t indicate a health problem and often goes unnoticed. This common condition can appear anywhere hair grows, including the scalp, beard, armpits, and pubic areas.
Consult a healthcare provider if the area around multiple hairs becomes painful, inflamed, itchy, or develops frequent ingrown hairs. Signs of infection, such as pus-filled bumps or persistent discomfort, warrant a visit to a dermatologist.