Seborrhoeic dermatitis and seborrhoeic blepharitis - Irish Medical Times

In the first part of this article, Pharmacist Eamonn Brady focuses on seborrhoeic dermatitis and in the second part he discusses the closely linked seborrhoeic blepharitis, an underdiagnosed inflammatory eye condition, mainly caused by seborrhoeic dermatitis

Dermatitis' is a red, itchy, flaky skin condition caused by inflammation; "Seborrhoeic" refers to a rash that affects greasy (sebaceous) skin zones that occur on the face, scalp and centre of the chest. Seborrhoeic dermatitis (SD) is also known as seborrhoeic eczema.

Part 1: Seborrhoeic dermatitis
Seborrhoeic dermatitis (SD) is very common and many people do not realise they have it. It has been reported to affect about 4 per cent of the population, and dandruff (which is mild SD of the scalp) can affect almost half of all adults. It can start at any time after puberty and is slightly commoner in men. Babies can also get a temporary form of SD in the scalp known as cradle cap and in the nappy area known as nappy rash which usually clears after a few months.

Causes
It is thought that SD is triggered by an overgrowth of a harmless fungus called Malassezia that lives on the skin, or an overreaction by the skin's immune system to this fungus. Malassezia is a normal component of skin flora, but in those with SD, the fungi invade the stratum corneum, releasing lipases that result in free fatty acid formation and cause the inflammatory process to begin. Malassezia thrive in high-lipid (fatty) environments, so the presence of free fatty acids in the seborrhoeic areas of the body enhances the growth of the fungi and making it more common on the face, scalp and centre of the chest.

SD is generally not linked to any underlying illness; but can be more persistent and severe in people with HIV infection and it is also common in people with Parkinson's disease. Tiredness, stress, and sun exposure can sometimes trigger a flare of SD. It is more common in cold than in warm weather, and it is not related to diet. It is not hereditary.

Symptoms
The symptoms of SD often vary from person to person. Affected areas can be itchy, painful, and sensitive and flaking skin can be bothersome and embarrassing, especially with dark clothing. Some people have the rash without any pain, itchiness, or irritation.

Skin in the affected areas is red with greasy looking skin flakes. It usually affects one or two body areas (scalp, face, chest) but can sometimes be more widespread.

Most common sites it affects are:

• Scalp: SD here ranges from mild flaky skin (dandruff) to a redder, scalier, and sometimes weeping rash.
• Face: It often affects the inner eyebrows and creases around the nose and cheeks. The eyelids may also become red, swollen, and flaky (seborrhoeic blepharitis [SB]).
• In and around the ears: Some people have inflammation inside the ear canals, in the cup of the ear and behind the ears. The skin can get infected with bacteria which result in oozing and crusting. Inflammation in the ear canal (otitis externa) can cause it to become blocked.
• Front of the chest and between the shoulder blades: It shows up as well-defined, round pink-red patches with mild scaling.
• In the skin folds: It can affect moist areas such as the skin under the breasts, in the groin, under the arms, or in folds of skin on the abdomen. The skin is pink and shiny with surface cracks.
• In darker skin: Affected areas may look lighter (hypopigmented) or darker (hyperpigmented) than surrounding skin.

Diagnosis
The diagnosis is made by examining the rash. It is not usually necessary to take a skin sample (biopsy) or to do any blood tests. If SD is severe or unresponsive to treatment and someone is at risk of HIV they may get tested. If there is a suspicion of ringworm of the scalp, then skin scrapings can be sent to look for tinea fungus (mycology).

Distinguishing from other conditions
Depending on the part of the body affected, other conditions which display similar symptoms should be discounted. On the scalp it should be differentiated from psoriasis, atopic dermatitis, and impetigo. On the face, rosacea, contact dermatitis, psoriasis, and impetigo should be discounted and, on the trunk, pityriasis versicolor and pityriasis rosea must be discounted.

SD can be difficult to distinguish from other kinds of dermatitis when certain areas such as the eyelid or genital area are affected or if it is very widespread. Severe scalp SD can resemble psoriasis. In psoriasis, the scales are thicker and whiter, and the face is not usually affected.

Prognosis
Treatment can improve and sometimes clear SD, but there is no permanent cure, and the complaint tends to come back when treatment is stopped.

Treatment
SD is managed with treatment that reduces the level of skin fungi including creams and shampoo, which can be used safely on a long-term basis. Mild steroid creams can be used for short periods if more severe skin irritation is an issue, and the newer non-steroid anti-inflammatory eczema creams (calcineurin inhibitors) are also effective though not licensed for SD.

How the main treatment options work
Keratolytics (sulfur and salicylic acid) help remove the outer layers of the hyper-proliferating stratum corneum. Coal tar is thought to decrease the rate of stratum corneum production. Antifungals such as ketoconazole decrease the Malassezia population, whereas anti-inflammatories such as corticosteroids and calcineurin inhibitors decrease the inflammatory response. The severity of symptoms can be affected by stress and sun exposure, and often has a variable course despite treatment.

Treatment options
Treatment is usually needed on a long-term basis or more accurately, preventative treatments once the worst flares-ups have settled. The choice depends on which areas of the body are affected and whether there is a lot of irritation. Many studies published over the years indicate that antifungal agents like ketoconazole have the highest success rates in treating and preventing SD and dandruff.

• Scalp: Medicated, anti-dandruff shampoos containing agents such as zinc pyrithione (Head and Shoulders®), selenium sulphide (Selsun®) or ketoconazole (Nizoral®) can be used regularly. For best results, wash into the scalp, then wait 5-10 minutes before rinsing. Thick scales can be removed before shampooing by applying a descaling preparation containing coconut oil and salicylic acid (Cocois® Ointment) for several hours or overnight before washing out. This can be messy, but it usually works well. If irritation is troublesome, the general practitioner (GP) may prescribe a steroid scalp lotion, gel, or shampoo for occasional use.
• Elsewhere on the body: Anti-fungal creams or ointments are usually effective and can be used safely as long-term treatment. Examples include clotrimazole (Canestan®) and miconazole (Daktarin®). They can be combined with a mild steroid for a few weeks if inflammation is an issue. Washing the body with an antifungal shampoo containing ketoconazole (such as Nizoral®) may also help. Leave the shampoo on for 5 minutes or so before rinsing it off.
• Ear canals: Medicated eardrops may help. The likes of olive oil drops can soften the skin if scaly. The doctor may prescribe steroid eardrops if very inflamed. Do not clean the ears with cotton buds as this causes more irritation.
• Eyelids: Carefully cleaning between the lashes with an eyelid cleanser or baby (non-sting) shampoo helps to lift skin flakes and reduce inflammation.

Occasionally, if the rash is widespread or resistant to the treatments listed above, the doctor may suggest a short course of an oral anti-fungal medication (e.g.) Terbinafine, Fluconazole.

Longer-term prevention
Once the scalp is clear, continual use of an anti-fungal shampoo like ketoconazole once a week reduces risk of the rash coming back. A plain moisturiser can help to reduce scaling and redness of the skin. Changing your diet is not likely to make any difference.

Part 2: Seborrhoeic blepharitis
Seborrhoeic blepharitis (SB) is linked to seborrhoeic dermatitis (SD). In some people, SD causes an inflammatory type of reaction in the eyelids and around the eyes leading to blepharitis.

Overall, there are three main types or causes of blepharitis. These are staphylococcal blepharitis, SB and meibomian blepharitis. While all three types cause similar symptoms, the causes are different. On rare occasions it is caused by an allergic reaction. This article focusses on SB caused by SD.

Symptoms of SB
Sore eyelids are the most common symptom; both eyelids are usually affected. Eyelids can look red, inflamed, and crusty. The eyes can become sticky with discharge, especially if an infection develops; the eyelids can stick together in the morning. In some cases, tiny flakes or scales can be noticed on the eyelids resembling small flakes of dandruff. Crusts sometimes develop at the base of eyelashes.

Treatment of SB
The condition can be controlled but there is no one-off cure for blepharitis. Regular treatment can ease symptoms and prevent flare-ups. Regular eyelid hygiene and hydration is central to any treatment regime. Treatment options that are sometimes needed, especially in bad flare-ups include antibiotics, steroid creams and specific treatments described earlier for SD when it is the main trigger. Rubbing your eyelids can make the inflammation worse, so should be avoided.

Regular eyelid hygiene
This is central to the treatment and prevention of blepharitis. This aims to soothe irritated eyes and eyelids, unplug blockages of the meibomian glands and clear stagnant oily secretions from these glands. The eyelids are cleaned, and debris is removed. The daily treatment regime consists of three parts which are applying warmth, massage, and cleansing. Contact lenses should be removed before starting the regime.

Warmth
The aim of applying heat is to soften the skin and any crust that forms on the eyelids. Heat makes oily secretions made by the meibomian glands less viscous so it can flow easier. The heat helps clear any blocked glands allowing oily secretions to flow more freely. Applying heat for 5 minutes is sufficient to have the desired effect. The traditional way of applying heat is to press on the eyelids gently with a warm facecloth (heated in hot water) for 5-10 minutes. When the facecloth cools, rewarm it with hot water.

Massage
After applying heat, it is important to massage the eyelids immediately. Massaging releases oily fluid from the tiny meibomian glands. To massage the eyelids, sweep a fingertip from the inner corner of the eye from the nose along the eyelid to the outer corner of the eye. Repeat this sweeping type of massage for 5 to 10 times for about 30 seconds followed immediately by warming. The massaging should not be too gentle or too firm and the eyes should be shut when massaging.

Clean
After warming and massaging the eyelids, the next step is to clean the eyelids. There is no one recommended method; a traditional method is using cotton wool buds dipped in diluted baby shampoo. After cleaning the eyelids with the cotton wool bud, it is important to wash off the shampoo from the eyelids before reopening the eyes to prevent irritation.

There are also special eyelid scrubs available from opticians or pharmacies. Simply washing the eyelids with cooled water that has recently been boiled is probably as effective as other methods.

The regimen of warmth, massage, clean should be completed at least twice daily until symptoms ease. When symptoms ease, it should still be continued once a day to prevent further flare-ups. For people prone to blepharitis, they should make this regimen part of their daily routine just like brushing teeth or shaving. For many, this can be the only way to prevent frequent flares.

Lubricants
In cases where dry eyes are an issue, artificial tear substitutes can help. These are available over the counter in pharmacies.

Antibiotics
Antibiotic eye ointment, gel or drops may be prescribed as a short-term course in cases where an eyelid becomes infected. For example, a course of chloramphenicol drops or fusidic acid gel. If prescribed an ointment for blepharitis, squeeze it on the edge of the eyelid (not directly on the eye) after cleaning the eyelid (as described above). Antibiotic tablets may be required for troublesome infected eyelids (e.g.) staphylococcus. A three-month course of antibiotics is often required for the treatment of blepharitis.

Eamonn Brady (MPSI), is owner of Whelehans Pharmacies in Mullingar.

References

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