Ocular cicatricial pemphigoid (ocular mucous membrane pemphigoid)

Pemphigoid is a family of autoimmune blistering conditions. The version that mainly involves the soft, moist linings of the body is called mucous membrane pemphigoid (MMP). The British Association of Dermatologists says that cicatricial pemphigoid, oral pemphigoid and ocular pemphigoid are other names for the same condition, with mucous membrane pemphigoid being the most up-to-date term. Cicatricial means scarring.

When the eyes are affected, the condition is called ocular mucous membrane pemphigoid, ocular MMP or ocular cicatricial pemphigoid. Moorfields explains that in ocular MMP the immune system makes autoantibodies that damage the conjunctiva, the thin mucous membrane that covers the eyeball and lines the inside of the eyelids. For many people with MMP the eyes are the only site affected, and Moorfields says that about 60% of people with MMP have the disease in their eyes as well as other mucous membranes or skin.

It is uncommon. Fight for Sight says one person in every million has ocular mucous membrane pemphigoid in the UK. Moorfields says it usually affects people over 40, both men and women, and the BAD leaflet says that MMP usually starts around the age of 70, although some cases have been reported in childhood.

The cause is not known. Moorfields says it has a genetic element but is not inherited, and the trigger is unknown. The BAD leaflet says it is considered an autoimmune disease and that it is not contagious or due to food allergy.

In the eye, the disease starts as conjunctivitis. Moorfields describes red, painful, sticky eyes that may be mild and intermittent or severe and persistent, and that do not improve with antibiotics or eye drops. The BAD leaflet similarly says the eyes may be red, gritty or sore, and that conjunctivitis may be diagnosed.

As the disease progresses, scarring changes the structure of the eyelids and eye surface. Moorfields lists the features below. Scarring occurs early but can be difficult to see with the naked eye until the disease is quite advanced.

• Red, painful, sticky eyes that do not respond to the usual treatments.

• A reduction in the depth of the pocket between the eyelids and the eyeball, which may show as a droopy lid or a smaller gap between the lids.

• Eyelids turning inwards and eyelashes scratching the surface of the eye (trichiasis).

• Dry eyes, because scarring and inflammation affect the tear-producing glands.

• In advanced or untreated disease, loss of vision.

Any red eye that does not settle with the first treatment, or keeps coming back, is worth getting reviewed. Moorfields says the conjunctivitis of this disease does not improve with antibiotics or eye drops, so persistent redness and soreness should be reviewed again rather than treated repeatedly in the same way. If you have a known diagnosis of MMP and your eyes become more painful or red or your vision changes, contact your specialist team promptly.

The BAD leaflet says that if active disease in the eye is not treated urgently it may lead to scarring and impaired vision, and that a diagnosis of MMP in the mouth is important because it alerts the specialist to the possibility that the eyes may become involved. If you have been told you have pemphigoid in the mouth or gums, you should have your eyes checked even if they feel comfortable.

Diagnosis can be difficult because the early picture looks like ordinary conjunctivitis or dry eye. The BAD leaflet says that MMP cannot be diagnosed on its appearance alone, as other conditions can look very similar. The diagnosis is usually confirmed by a biopsy. Fight for Sight explains that a small piece of tissue is taken from the conjunctiva, and anaesthetic drops are put in both eyes so that the biopsy is painless. The BAD leaflet says the samples are examined under a microscope and tested for specific antibodies, and a blood test may also be used to detect them.

Because several areas can be involved, referral to different specialists may be needed. The BAD leaflet lists an ophthalmologist for early signs in the eyes, an ENT specialist for ear, nose and throat symptoms, and a dermatologist or oral medicine specialist for the skin and mouth, and stresses that care from a multidisciplinary team is very important.

The aim of treatment is to control inflammation and to prevent scarring. Moorfields says that with the right treatment at the right level it is possible to halt the progress of the disease and achieve remission. The BAD leaflet says that for the eyes, treatment is directed by an ophthalmologist and may include lubricants, topical corticosteroid or other eye drops, although oral medication is needed for most patients.

The BAD leaflet describes a stepped approach to treating MMP in general, summarised below. The doctor will discuss the options and help choose the most suitable, depending on severity, general health and potential side effects.

Moorfields says that the disease progresses at different rates in different people, with rapid progression over weeks in a minority and slow progression over months or years in most. Early diagnosis in severe cases improves outcomes, and with good treatment the effects can usually be controlled and both comfort and eyesight maintained. It also says that currently it is not possible to reverse the blindness that very bad or untreated disease can cause.

The BAD leaflet says that MMP is usually brought under control with tablets or injections, that tablets may be needed for several years, and that in some people the condition goes into long-term remission, after which medication may eventually be stopped. Fight for Sight notes that the rate at which scarring progresses can vary and that irreversible sight loss can occur in particularly severe cases.

For self-care of the mouth, the BAD leaflet suggests regular dental checks, a soft toothbrush and a mild-flavoured toothpaste free from sodium lauryl sulphate, and stopping smoking. For the eyes, it says to seek precise advice from your ophthalmologist.

Support is available. Moorfields and the BAD leaflet mention the PEM Friends patient support group.