What is Seborrheic dermatitis? – Symptoms, Causes, and Treatments

Seborrheic dermatitis – Overview

Seborrheic dermatitis, a chronic type of eczema, develops on the scalp, upper back and other areas of the body with high sebum production in the sebaceous glands, which produce oil. Symptoms can range from dandruff on hair to a rash on the affected area.

Seborrheic dermatitis typically clears up on its own in many infants and some adults. There are numerous efficient treatments to manage symptoms and prevent future flare-ups of seborrheic dermatitis if symptoms don’t go away.

This skin condition is characterised by the greasy, yellowish scale on an erythematous background. It affects the scalp, external ear, middle face, upper trunk, underarms and groin—areas rich in sebaceous glands. Scalp and other hair-bearing areas are covered in a white scales that is the most prevalent and mildest type of dandruff without any underlying erythema.

Clinical diagnosis of seborrheic dermatitis—a chronic and recurrent disorder—is possible. It often improves during summer, especially with ultraviolet exposure, and gets worse in a cold, dry climate. Additionally, stress is likely to start or exacerbate flares. Seborrheic dermatitis patients have an excess of Malassezia, a yeast that is typically present on the skin.

It is unclear why some people develop seborrheic dermatitis while others do not, but the cause most likely has to do with variations in the way the immune system reacts to Malassezia. Interestingly, Malassezia and the typical Candida yeast prevalent in the GI tract share immunological cross-reactivity. 

Increased amounts of Candida antigen have been discovered in the faeces and on the tongue of people with seborrheic dermatitis, pointing to possible higher levels in the GI tract. Additionally, some patients receiving oral anti-yeast drugs do experience an improvement in their seborrheic dermatitis.

In patients with Parkinson’s disease and HIV, seborrheic dermatitis can be more severe and challenging to treat. Treating these illnesses can also improve seborrheic dermatitis.

Clinical Features 

Infantile Seborrheic dermatitis 

Infantile seborrheic dermatitis results in a Cradle cap (diffuse, greasy scaling on the scalp). The armpit and groin folds may become affected by the rash as it progresses.

There are salmon-pink areas that could flake or peel.

Even when generalised, the rash does not usually bother the baby much because it is not very irritating.

Adult Seborrheic dermatitis 

Seborrheic dermatitis usually affects areas of the skin with significant sebum production, including the scalp, nasolabial folds, glabella, eyebrows, beard, ears, retro auricular skin, sternum and other skin folds.

Common characteristics include

• Winter flares that improve after sun exposure in the summer
• Slight itch
• Dry and oily combination midface skin
• Scaly scalp patches or scattered scales that are ill-defined
• Blepharitis causes scaly, crimson eyelid borders.
• Salmon-pink plaques in the skin fold on both sides of the face that are thin, scaly and poorly defined.
• Rash visible in the armpits, under the breasts, in the groyne folds and in the genital creases. Petal- or ring-shaped flaky patches on the hairline and on the anterior chest.
• Malassezia folliculitis (inflamed hair follicles) is present on the cheeks and upper trunk.
• Pityriasiform seborrhoeide describes severe seborrheic dermatitis that affects the scalp, neck and trunk.

What causes Seborrheic dermatitis? 

A combination of genetic and environmental factors contributes to seborrheic dermatitis.

The primary cause is typically an allergic reaction to Malassezia yeast, also known as pityrosporum. Seborrheic dermatitis is most likely caused by this organism, which often resides on the surface of the skin. The immune system overreacts to the Malassezia as it overgrows, which leads to a fungal infection that alters the skin.

Psoriasis, acne, epilepsy, rosacea, HIV, Parkinson’s disease, alcoholism, eating disorders, depression and recovery from a stroke or heart attack are among the illnesses that can make someone more likely to develop seborrheic dermatitis.

Symptoms of Seborrheic dermatitis 

The rash is typically red and scaling, although, on rare occasions, it may also become weepy and oozy. The patient’s main complaint may be the widespread scaling, which might lead to severe dandruff. 

The scalp, outer ear and external auditory canal, as well as the forehead, brows, eyelids and cheeks, including the folds that run from the nose to the sides of the mouth, are areas of the adult body that are frequently prone to this skin condition. 

Less frequently affected areas include the armpits, mid-chest and mid-back. The rash in babies leads to a scalp eruption known as cradle cap. The diaper area may also be affected, making it a more severe situation. In particular, the scalp usually itches from it.

Who are at risk for Seborrheic dermatitis? 

Seborrheic dermatitis frequently results from triggers like,

• Recovery from stress caused by a traumatic life event, such as a heart attack or the death of a close one.
• Strong detergents, solvents, chemicals or soaps. 
• Hormonal changes or sickness.
• Some drugs include psoralen, interferon and lithium. 
• Various climatic circumstances, such as cold, dry weather or a change in season. Some medical diseases, such as HIV and Parkinson’s disease.

As with all eczema types, seborrheic dermatitis is not communicable. It is not something one can get from someone else. It is the outcome of genetic and environmental influences.

Seborrheic dermatitis diagnosis 

Self-assessment 

Note the symptoms of the rash before making an appointment. A doctor will ask several questions regarding the rash (also known as spots or patches), including where the lesions are located, what makes it better or worse, whether there are any accompanying symptoms like itching or burning, and whether the rash is ongoing or episodic.

Despite the temptation to self-diagnose, there are several conditions that this skin condition mimics. A dermatologist or primary care physician will be able to make the best diagnosis, rule out other potential causes and suggest the most suitable course of action.

Laboratory test 

A healthcare provider will note the precise location of the rash during skin examination in addition to observing the characteristics of the rash (such as the presence of scaling).

Only areas of the body with an abundance of sebaceous or oil-producing glands, such as the scalp, middle of the face, ears, eyebrows, upper chest and back, armpits, and genitals, may experience the rash in seborrheic dermatitis.

A dermatologist might take a skin biopsy if seborrheic dermatitis is still difficult to diagnose. A biopsy involves taking a small sample of the affected skin and examining it under a microscope.

If different diagnoses are under consideration, more tests could be carried out. To rule out a fungal infection, which can mimic seborrheic dermatitis, a KOH prep test might be performed. 

Similarly, a healthcare professional may consider seborrheic dermatitis a symptom of an underlying medical condition for which blood or other tests may be prescribed.

Treatment for Seborrheic dermatitis 

Scalp and beard areas 

Shampooing every day or on alternate days with antidandruff shampoos containing 2.5 per cent selenium sulphide or 1 to 2 per cent pyrithione zinc is an effective treatment for many types of seborrheic dermatitis. 

Ketoconazole shampoo is an alternative option. The shampoo must be used on the scalp and beard areas and kept on for five to ten minutes before being rinsed. To stop the hair from drying out, use a hydrating shampoo afterwards. 

The frequency of medicated shampoo use may be reduced to twice weekly or as necessary after the disease is under control. Scalp seborrhea has also been successfully treated with a 1% topical terbinafine solution.

Body 

When treating seborrhea on the trunk, zinc or coal tar shampoos should be used often, as should zinc soaps. A topical corticosteroid cream, lotion or solution administered once or twice per day will also be beneficial. 

Topical ketoconazole cream, 2 per cent, may also be used. Washes with benzoyl peroxide are also excellent for managing trunk seborrhea. After using these agents, patients should be advised to rinse as they will bleach clothing and bed linens properly. The patient may benefit from applying a moisturiser after therapy if these agents are drying.

Face 

Shampoos that are effective against seborrhea may be used often to wash affected parts of the face. As an alternative, 2% ketoconazole cream can be used in the afflicted regions once or twice a day. 

It is typically recommended to apply 1 per cent hydrocortisone cream once or twice daily to affected areas to help reduce erythema and irritation. Another efficient topical treatment for seborrheic dermatitis is 10% sodium sulfacetamide cream.

Extreme Seborrhea 

After four weeks of medication, severe seborrhea may improve with isotretinoin treatment in doses as low as 0.1 to 0.3 mg per kg daily. After that, maintenance medication with a dose as low as 5 to 10 mg/day lasting several years may be successful. 

However, few patients with seborrhea are suitable candidates for treatment because isotretinoin has potentially harmful side effects. Most corticosteroids come in the form of solutions, lotions, creams and ointments. Ointments may be a better option.

Preventing Seborrheic dermatitis 

Yeast elimination diet 

Yeast and mould exclusion diets may be beneficial for persons who have trouble managing their seborrheic dermatitis, although there is no strong clinical research in this area. This means avoiding foods made with yeast or fungi, as well as bread, cheeses, wine, beer and large amounts of carbs. 

Combining this type of diet with high-quality probiotics increases the likelihood that the gut will become repopulated with beneficial bacteria and yeast.

Vitamins and minerals 

Biotin is helpful for breastfeeding mothers. In newborns with seborrheic dermatitis, biotin has been used to treat the condition. There are no adult trials, and the results have been inconsistent. But supplementing with biotin is safe. Biotin food sources include egg yolk, liver, bananas, avocados, carrots and cauliflower. A daily dose of 5 to 10 mg is recommended.

Omega-3 fatty acids reduce the synthesis of inflammatory substances. Omega-3 fatty acids should ideally be obtained through fatty fish (such as mackerel, salmon and sardines), flaxseeds and walnuts. Supplements may be beneficial if that is not possible. Daily flax oil intake should be one tablespoon for 100 lb. Daily consumption of 1-2 tablespoons of ground flaxseed. 1-2 mg of fish oil twice a day is advisable. 

Making healthy food choices is crucial for overall wellness. Many elements of health have been proven to be improved by anti-inflammatory or Mediterranean-style dietary approaches, particularly when inflammatory illnesses are present. 

Seborrheic dermatitis is an inflammatory disorder that may get better by choosing foods that reduce inflammation.

Skincare 

Tea Tree Oil

Seborrheic dermatitis-related yeasts can be killed by tea tree oil. Undiluted tea tree oil is never applied directly to the skin since it can result in contact dermatitis.

Quassia Amara

This evergreen shrub, which also goes by the names Bitterwood and Amargo, is located in northern South America. Several of the substances it contains have antifungal and anti-inflammatory activities. This is a safe, efficient substitute for seborrheic dermatitis therapies that are more often used. Applying a thin layer of 4% gel one to twice daily is advisable.

Solanum Chrysotrichum 

Solanum Chrysotrichum plant has been used to treat skin fungus infections. It has been demonstrated that a leaf extract in 5% methanol is active against several dermatophytes. For four weeks, apply 5% Chrysotrichum shampoo three times each week.

Avocado Oil

Applying oil can aid in removing the scale due to seborrheic dermatitis. Since this natural oil is thicker than many other oils and certain of its constituents contain antifungal properties, avocado oil can be very soothing to damaged skin.

When to refer a doctor? 

If the symptoms worsen or if there is a significant flare-up, one should visit a healthcare physician. In this situation, a doctor can assist in changing the dosage of the medicine or choosing an alternative course of therapy.

A healthcare professional might request a skin biopsy. This occurs when a tiny portion of the skin is removed so that it may be examined in a lab. The doctor can select the best course of treatment based on the results of the skin biopsy.

Conclusion 

Seborrheic dermatitis may be self-limiting. However, recovery time may be prolonged. Infants’ cradle caps typically go away after a few weeks or months. While the symptoms can be bothersome, numerous efficient treatment options are available. 

In adults, the disease is typically chronic, and long-term maintenance treatment is frequently required. Even the most severe instance should be manageable to a treatment strategy after speaking with a healthcare practitioner.

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