Why do I have multiple hairs growing from the same opening in my skin?

Introduction

The emergence of more than one hair fiber from a single follicular opening in the skin is a phenomenon that garners significant interest in dermatological and trichological research. This occurrence, while sometimes physiological, can also indicate an underlying pathological condition. This overview aims to explore the various scenarios under which this phenomenon occurs, shedding light on the etiology, clinical presentation, and implications of having several hair fibers growing from the same outlet.

Having several hairs, or even a bunch of hairs, growing out of the same hole in the skin could be a result of:

1. Physiologic Hair Change

In normal hair cycle dynamics, the coexistence of old (telogen phase) and new (anagen phase) hairs in the same follicle is occasionally observed. This simultaneous presence is typically a transient and benign condition, reflecting the natural hair growth cycle. It is entirely normal and the issue should resolve itself as the old telogen hair should fall out at some point. However, its persistence may necessitate further examination to rule out any underlying scalp disorders, especially if the follicle is inflamed.

2. Trichostasis Spinulosa (Thysanothrix)

Trichostasis spinulosa is a condition characterized by the retention of numerous short, dead hairs within a single follicle. This condition is often misdiagnosed as “blackheads”, particularly when occurring on the nose or the back skin. The retention of hair fragments results from a disruption in the normal shedding process, leading to a plug-like formation within the follicle. Trichostasis spinulosa is more of a cosmetic concern than a medical one, but its presence can be indicative of poor hair follicle health. It tends to be treated by tweezing, depilatory waxing, or topical retinoic acid creams.

3. Compound Follicles

Compound follicles, where the necks of multiple follicles merge into a common opening to the skin surface (called an infundibulum), represent a unique structural anomaly. This condition can lead to several hairs emerging from a single opening. Compound follicles can clinically look very similar to pili multigemini follicles. The key difference between the two is that with compound follicles, several dermal papillae situated very close together each control the growth of a separate hair fiber; whereas with pili multigemini several hair fibers are made by a single dermal papilla. This difference can only really be observed in scalp biopsies. Understanding compound follicles is crucial for dermatologists, as this condition can affect hair density and scalp health assessments. It is generally not a medical problem, but if the follicles become inflamed they can be surgically removed.

4. Congenital Sinuses and Cysts

Congenital sinuses and cysts encompass a range of conditions, including preauricular sinuses, pilonidal cysts, dermoid cysts, and folliculomas. These conditions are differentiated by their locations and the types of tissues involved. In each case, multiple hair roots may arise from the epithelial wall of the cyst or sinus, potentially leading to several hairs emerging through a single external opening. These conditions, especially pilonidal cysts and dermoid cysts, can pose significant clinical challenges due to their potential for infection and even recurrence after surgical removal.

5. Multiple Hairs (Pili Multigemini)

Pili multigemini is a fascinating condition wherein a single follicle gives rise to multiple hair shafts. This diagnosis is subdivided into true multigeminate hairs, where several shafts are formed from a single papilla but are individually sheathed, and composite hairs, where the shafts are partly merged together. Pili multigemini hair follicles are considered rare. Although there have been no studies to define the actual frequency in the general population, it is believed to be relatively more common in men’s beards and children’s scalps. Pili multigemini is particularly interesting as it challenges the traditional understanding of one hair produced per follicle. While typically benign, this condition can sometimes lead to hair grooming difficulties and folliculitis. Where necessary, the pili multigemini follicle can be surgically removed. Read our pili multigemini page for more details.

6. Split Hairs (Fragilitas Crinium)

Fragilitas crinium, more commonly known as “split hairs”, involves the longitudinal splitting of the hair shaft, which can extend into the follicle inside the skin. This condition is often a result of mechanical or chemical hair shaft trauma. While it results in the appearance of multiple hairs emerging from one follicle, it is actualy one hair split lengthways into multiple strands. It is primarily a hair shaft disorder rather than a follicular issue. Management typically involves addressing the underlying cause and improving cosmetic hair care practices.

7. Tufted hair folliculitis

Tufted hair folliculitis is a rare scalp condition that leads to scarring hair loss. As part of the disease, numerous hair tufts arise from enlarged follicular openings. This tufting is due to neighboring hair follicles clustering together due to a fibrotic scarring process and the retention of resting-phase (telogen) hairs in these widened openings. Several causative theories exist for this condition, including developmental abnormalities, repeated follicular infections, and the accumulation of telogen hairs within these tufts.

Discussion

The emergence of multiple hairs from a single follicular opening presents a range of diagnostic challenges and insights into hair follicle biology. From a physiological standpoint, this phenomenon highlights the dynamic nature of the hair growth cycle. Pathologically, it can be indicative of scalp and hair disorders, requiring careful examination and management.

Each of these conditions has its own set of implications. For instance, compound follicles and pili multigemini can affect hair density and texture, while conditions like trichostasis spinulosa and fragilitas crinium can have cosmetic impacts. Congenital sinuses and cysts, due to their potential for infection and recurrence, represent a more serious clinical concern.

Conclusion

Understanding the various conditions under which multiple hairs emerge from a single opening is crucial for dermatologists and trichologists. It aids in the accurate diagnosis and management of hair and scalp disorders. Moreover, it provides insights into the complex biology of hair follicles, paving the way for future research and therapeutic advancements in the field of hair and skin disease. The study of these conditions not only enriches our knowledge of hair follicle pathology, but also underscores the importance of holistic understanding in dermatological practice.

In conclusion, the occurrence of multiple hairs emerging from a single follicular opening represents a fascinating intersection of physiological, structural, and pathological processes. A comprehensive understanding of these conditions is essential for clinicians and researchers alike, as it contributes to better diagnosis, treatment, and potentially, prevention of related hair and scalp disorders. This area of study remains a fertile ground for further research, promising new insights into the complex world of hair biology and dermatology.

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