Distichiasis: Symptoms, Types, Causes and Treatment

Distichiasis is a rare but impactful condition involving abnormal growth of eyelashes. For those affected, it can cause significant discomfort and even lead to more serious eye complications. Understanding the symptoms, types, causes, and treatment options is essential for both patients and healthcare professionals. This article provides a comprehensive look at distichiasis, synthesizing the latest scientific findings to offer clear, accessible guidance.

Symptoms of Distichiasis

Distichiasis can present in a variety of ways, ranging from mild irritation to more serious eye issues. Early recognition of symptoms is important to prevent complications and seek timely treatment. Let's take a closer look at the common signs and how they might affect daily life.

Symptom	Description	Severity/Impact	Source(s)
Extra eyelashes	Accessory lashes from meibomian gland orifices	Can be partial or complete; may be asymptomatic	1 4 8
Eye irritation	Discomfort or foreign body sensation	Mild to severe, depending on lash contact	8
Redness	Reddened eyelid or eye surface	Often accompanies irritation	8
Tearing (Epiphora)	Excess tear production	May cause blurry vision	8
Photophobia	Sensitivity to light	Sometimes present in syndromic cases	3
Corneal issues	Ulceration, keratitis	Can occur if lashes rub the cornea	7 8

Table 1: Key Symptoms

Understanding the Range of Symptoms

Distichiasis is most easily recognized by the presence of an extra row of eyelashes emerging from the openings of the meibomian glands, located at the posterior margin of the eyelid 1 8. In some individuals, only a few additional lashes are present, while in others, the accessory row may be complete.

Severity and Impact on Daily Life

The symptoms caused by these extra lashes depend largely on their number, orientation, and the degree of contact with the eye surface. Key issues include:

• Irritation and Redness: The abnormal lashes may rub against the cornea or conjunctiva, leading to persistent irritation, redness, and a sensation of a foreign body in the eye 8.
• Tearing (Epiphora): Reflex tearing is common, as the eye tries to wash away the offending lashes 8.
• Corneal Complications: In more severe cases, chronic friction can lead to keratitis (inflammation of the cornea), corneal ulcers, and even loss of vision if left untreated 7 8.
• Photophobia: Increased sensitivity to light has been reported, especially in syndromic forms of distichiasis 3.
• Variable Symptom Severity: Some people remain asymptomatic, especially if the extra lashes are soft or do not contact the cornea 4.

When to Seek Help

If you notice persistent eye discomfort, unexplained tearing, or see extra lashes at the back edge of your eyelids, consult an ophthalmologist for assessment. Early intervention can prevent more serious eye damage.

Types of Distichiasis

Distichiasis is not a one-size-fits-all condition. It can differ in its origin, presentation, and associated features. Understanding the different types is key for accurate diagnosis and effective management.

Type	Characteristics	Associated Conditions	Source(s)
Congenital	Present at birth; often familial; autosomal dominant	Lymphedema, heart defects	1 2 3 4 5 6
Acquired	Develops later; secondary to disease or trauma	Inflammation, scarring	1
Syndromic	Part of lymphedema-distichiasis syndrome (LD)	Lymphedema, varicose veins, cleft palate	2 3 4 6

Table 2: Major Types of Distichiasis

Congenital Distichiasis

Congenital distichiasis is typically inherited in an autosomal dominant fashion and is present from birth 1 2 3 4 5 6. It is characterized by the development of an extra row of eyelashes that emerge from the openings of the meibomian glands, rather than their usual location on the eyelid margin 1. Histopathologically, these lashes arise from abnormal pilosebaceous units within the eyelid's posterior lamella 1.

Syndromic Forms

A significant subset of congenital cases is associated with lymphedema-distichiasis syndrome (LD), a multisystem genetic disorder caused by mutations in the FOXC2 gene 2 3 4 5 6. In addition to extra lashes, affected individuals may develop:

• Lymphedema: Swelling of the limbs, typically starting at puberty 2 3 4 5 6
• Other features: Congenital heart disease, cleft palate, ptosis (droopy eyelids), varicose veins, and spinal extradural cysts 4

Acquired Distichiasis

Acquired forms of distichiasis are less common. They typically arise secondary to chronic inflammation, scarring, or trauma to the eyelid, which leads to the transformation of meibomian glands into hair follicles 1. These cases are not inherited and can develop at any age.

Clinical Presentation

• Partial vs. Complete: The accessory lash row can be partial (affecting only a segment of the eyelid) or complete (spanning the entire lid) 1 8.
• Symptomatic vs. Asymptomatic: While some people experience significant discomfort, others may have no symptoms at all, especially if the lashes are fine and do not contact the eye surface 4.

Causes of Distichiasis

Understanding the root causes of distichiasis is crucial, especially for guiding treatment and genetic counseling. The etiology can be genetic or acquired, with the most well-studied mechanism involving mutations in a key developmental gene.

Cause	Mechanism	Inheritance/Origin	Source(s)
FOXC2 Mutation	Disrupts forkhead transcription factor, affecting eyelid & lymphatic development	Autosomal dominant	2 3 4 5 6
Developmental Error	Abnormal pilosebaceous units in eyelid	Congenital	1
Inflammation/Trauma	Meibomian gland transforms into hair follicle	Acquired	1

Table 3: Main Causes of Distichiasis

Genetic Origins: The FOXC2 Connection

The most common inherited cause of distichiasis is a mutation in the FOXC2 gene, which encodes a forkhead family transcription factor 2 3 4 5 6. This gene is vital for normal development of both the lymphatic system and eyelid structures.

• FOXC2 Mutation Effects: Mutations can result in a truncated or dysfunctional protein, leading to abnormal hair follicle development within the eyelid and defective lymphatic vessels 2 3 4 5 6.
• Autosomal Dominant Inheritance: The genetic defect is passed in families with a 50% chance of transmission from an affected parent to a child 2 3 5 6.
• Variable Penetrance: Not everyone who inherits the mutation will show all the features; there is significant variability in symptoms even within the same family 4 6.

Developmental Abnormalities

In congenital cases, the underlying problem is the presence of abnormal pilosebaceous (hair follicle and sebaceous gland) units in the posterior eyelid lamella, which give rise to the accessory lashes 1.

Acquired Causes

Acquired distichiasis is less common and may occur due to:

• Chronic eyelid inflammation (blepharitis)
• Trauma
• Scarring disorders (e.g., Stevens-Johnson syndrome)

These processes can induce transformation of meibomian glands into lash-producing follicles 1.

Treatment of Distichiasis

Treatment for distichiasis is tailored to the severity of the condition and the degree of discomfort or ocular damage it causes. Options range from conservative approaches to surgical interventions, each with their own benefits and risks.

Treatment	Method/Approach	Effectiveness/Notes	Source(s)
Epilation	Manual removal of lashes	Temporary	8
Cryotherapy	Freezing aberrant follicles	High success, risk of lid changes	8 10
Electrocautery	Heat to destroy follicles	Effective, some recurrence	11
Trephination	Microtrephine removes follicle	Safe & effective, low recurrence	9
Surgical Excision	Partial tarsal plate excision	Good results, some recurrence	7
Conservative	Lubricating drops, monitoring	For mild/asymptomatic cases	8

Table 4: Main Treatment Options

Conservative and Non-Surgical Approaches

• Epilation: Simple removal of problematic lashes with forceps provides temporary relief but must be repeated frequently as lashes regrow 8.
• Lubrication: Artificial tears and ointments can help protect the cornea if symptoms are mild and lashes are soft 8.

Cryotherapy

Cryotherapy involves freezing the aberrant follicles, usually via a transconjunctival approach. This method offers a high rate of symptom resolution without the need for retreatment in most cases 8 10.

• Advantages: Effective, can selectively target posterior follicles while sparing normal lashes 10.
• Risks: Possible long-term keratinization (thickening) of the eyelid margin, which may require additional treatment such as retinoic acid therapy 8.

Electrocautery

Transconjunctival thermal electrocautery uses heat to ablate the lash follicles. Studies in canine models show high success rates, with most patients needing only a single treatment and minimal complications 11.

• Recurrence: Some recurrence is possible, but usually without significant symptoms 11.

Eyelash Trephination

A newer technique, eyelash trephination, uses a microtrephine to core out the offending follicle. It is described as safe, quick, and effective, with a low recurrence rate and minimal adverse effects 9.

Surgical Excision

Partial tarsal plate excision, especially via a transconjunctival route, has shown excellent outcomes in both dogs and humans 7. It is particularly useful for cases where other methods have failed or when many lashes are involved.

• Complications: Potential for trichiasis (misdirected lashes) or cicatricial entropion (scarring-related inward turning of the lid), but these are typically manageable 7.

Choice of Therapy

• Mild/Asymptomatic Cases: Observation or conservative management
• Symptomatic/Severe Cases: Cryotherapy, electrocautery, trephination, or surgical excision depending on the number and location of aberrant lashes
• Refractory/Complex Cases: Multimodal or repeated interventions may be needed

Conclusion

Distichiasis is a complex condition that can have a significant impact on ocular health and quality of life. Understanding its symptoms, types, causes, and treatment options is crucial for effective management.

Key Takeaways:

• Distichiasis involves an extra row of eyelashes, often emerging from the meibomian gland openings 1 8.
• Symptoms range from mild irritation to severe corneal damage, with some cases remaining asymptomatic 8.
• Types include congenital (often genetic), acquired, and syndromic forms such as lymphedema-distichiasis syndrome (LD) 1 2 3 4 5 6.
• Causes are most commonly genetic mutations in the FOXC2 gene, but can also result from inflammation or trauma 2 3 4 5 6 1.
• Treatment options are varied—from conservative approaches to advanced surgical techniques, with cryotherapy, electrocautery, and eyelash trephination offering effective solutions 8 10 11 9 7.

If you or someone you know experiences symptoms suggestive of distichiasis, seeking prompt evaluation by an eye care professional can prevent complications and ensure the best possible outcome.