What Is Distichiasis?

Overview

Distichiasis is a rare condition that results in two rows of eyelashes. The second row may be complete, partial, or have only a few extra lashes. The extra lashes grow from the meibomian glands on the inner edge of the eyelid. Distichiasis can cause symptoms such as eye irritation, redness, watery eyes, light sensitivity, and corneal damage. Distichiasis can be present at birth (congenital) or develop later in life (acquired). Congenital distichiasis is often associated with a genetic syndrome called lymphedema-distichiasis syndrome, which causes swelling of the limbs and other problems. Treatment for distichiasis depends on the severity of the symptoms and may include eye drops, contact lenses, epilation (removal of the entire hair from the root), electrolysis, cryotherapy, or surgery.¹

Causes of distichiasis

The causes of distichiasis depend on whether it is congenital or acquired. Congenital distichiasis is usually caused by a genetic mutation of the FOXC2 gene, which affects the development of the lymphatic and blood vessels. This mutation can also cause a syndrome called lymphedema-distichiasis syndrome, which involves swelling of the limbs and other problems. 

Acquired distichiasis is caused by inflammation or injury of the eyelid, which can affect the meibomian glands and cause them to produce extra lashes. Some conditions that can cause acquired distichiasis are blepharitis, Stevens-Johnson syndrome, ocular cicatricial pemphigoid, and chemical injury to the eye.

Signs and symptoms of distichiasis

The signs and symptoms of distichiasis may vary depending on the number, length, and direction of the extra lashes. Some people may not have any symptoms at all, while others may experience:

• Visible extra eyelashes on one or both eyelids, usually emerging from the inner edge of the eyelid
• Redness, swelling, or irritation of the eyes or eyelids, especially if the extra lashes rub against the eye surface
• Feeling like something is in the eye, which can cause discomfort or pain 
• An infection of the eyelid that causes a painful bump (stye), which can result from the extra lashes blocking the meibomian glands 
• Sensitivity to light (photophobia), which can make the eyes water or squint 
• Watery eyes, which can occur due to irritation or dryness of the eye surface 
• Frequent bouts of pink eye (conjunctivitis), which can cause redness, itching, discharge, and crusting of the eyes 
• Eye pain, which can be severe if the extra lashes scratch or damage the cornea (the clear front layer of the eye)
• Scratches or scars on the cornea, which can impair vision or cause infections

Diagnosis of distichiasis

The diagnosis of distichiasis is usually made by examining the eyelids with a slit-lamp microscope, which allows the eye specialist to see the extra lashes emerging from the meibomian gland openings or touching the eye surface. The diagnosis may also include checking for other conditions that may be associated with distichiasis, such as lymphedema-distichiasis syndrome or cicatrizing conjunctivitis.

Management and treatment for distichiasis

The management and treatment of distichiasis depend on the severity and the number of extra lashes causing problems. Some possible options are:

• Eye drops or ointments to lubricate the eye and reduce irritation or inflammation
• Contact lenses to protect the cornea from the extra lashes
• Epilation to pluck out the extra lashes with forceps or tweezers. This is a temporary solution, as the lashes will grow back in a few weeks.
• Electrolysis destroys the hair follicles with an electric current. This can be done under local or general anaesthesia and may require multiple sessions.
• Cryotherapy to freeze and kill the hair follicles with liquid nitrogen. This can also be done under local or general anaesthesia and can cause scarring or depigmentation of the eyelid.
• Surgery to remove the extra lashes or the affected part of the eyelid. There are different surgical techniques that can provide a permanent cure but may also cause complications such as eyelid deformity, recurrence, or dry eye.

FAQs

Can distichiasis be prevented?

Some possible ways to prevent distichiasis are:

• If you have a genetic condition that causes distichiasis, such as lymphedema distichiasis syndrome, you can consult a genetic counsellor
• If you work with chemicals or other substances that can injure your eyes, wear proper protective equipment
• If you have an infection or inflammation on the eyelids, such as blepharitis or trachoma, seek medical treatment and follow hygiene measures^.

How common is distichiasis?

Distichiasis is estimated to happen in about 1 in 10,000 people. It can be present at birth (congenital) or happen later in life (acquired). 

Who is at risk of distichiasis?

The risk factors for distichiasis depend on whether it is congenital or acquired. For congenital distichiasis, the biggest risk factor is genetics. You're more likely to inherit the condition if one of your parents has it. About 75% of people who have lymphedema-distichiasis syndrome (LDS), a rare genetic disorder that causes distichiasis and lymphedema, have a parent with the disorder. LDS is caused by a mutation of the FOXC2 gene on chromosome 16.

For acquired distichiasis, the risk factors are related to certain conditions that cause inflammation or injury of the eyelid. These include chronic blepharitis, seborrheic dermatitis, ocular cicatricial pemphigoid, trachoma, chemical injury and Stevens–Johnson syndrome. These conditions can cause the meibomian glands to develop into hair follicles and produce extra lashes. Acquired distichiasis is more common in older people and in those assigned female at birth.¹

When should I see a doctor?

You should see a doctor for distichiasis if you have any of the following symptoms:

• Eye pain, swelling, redness or irritation
• Sensitivity to light
• Watery eyes
• Frequent bouts of pink eye (conjunctivitis)
• Styes (small, painful bumps on your eyelid)
• Scratches or scars on your cornea
• Droopy eyelids (ptosis)
• Vision loss

A doctor can examine your eyelids and confirm the diagnosis of distichiasis and will also recommend the best treatment options for your condition.

Summary

Distichiasis is a rare condition that results in two rows of eyelashes. The extra lashes grow from the meibomian glands. Distichiasis can be present at birth (congenital) or happen later in life (acquired). Congenital distichiasis is often caused by a genetic mutation of the FOXC2 gene, which can also cause lymphedema-distichiasis syndrome (LDS), a rare disorder that involves fluid accumulation in the body's tissues. Acquired distichiasis is caused by inflammation or injury of the eyelid due to various conditions, such as blepharitis, ocular cicatricial pemphigoid or Stevens-Johnson syndrome. Distichiasis can cause symptoms such as eye irritation, redness, swelling, stye, sensitivity to light, watery eyes, conjunctivitis, eye pain and corneal damage. Visit your healthcare provider if you experience any of these symptoms. Your healthcare provider will confirm your diagnosis by examining the eyelids with a slit-lamp microscope and also conducting tests to check for other conditions that might be responsible for distichiasis. Once the diagnosis is confirmed, you will get started with the treatment, which depends on the severity of the condition and may include eye drops, soft contact lenses, epilation, electrolysis, cryotherapy or surgery.