What is Seborrheic Dermatitis?
Seborrheic dermatitis (SD) is a common skin condition that causes symptoms such as flaky, scaly skin to form in areas where we have a lot of oil-producing glands, like the scalp, face, and body folds. This condition can happen at different stages of life, and there are two main types, one that affects infants and one that affects adults.
In babies, the condition often shows up as firm, oily scales on the top and front of the scalp. This can greatly worry parents, but usually shows up within the first three months of a child’s life, is not severe, and in most cases, gets better on its own by the first year.
In contrast, the adult form of the condition comes and goes throughout a person’s life. This type of SD can greatly affect someone’s quality of life and is considered one of the most impactful skin conditions, coming third after skin conditions called atopic and contact dermatitis.
What Causes Seborrheic Dermatitis?
Several different factors contribute to the development of Seborrheic Dermatitis (SD), a skin condition, and these diverse factors have led to many theories about what causes the condition and how it develops. The beginnings of SD seem to be tied to a mix of factors, including microscopic organisms normally found on the skin (especially a type called Malassezia spp.), the types of fats found on the surface of the skin, and individual susceptibility. Interestingly, neither the amount of oil the skin produces nor the amount of yeast present seem to be significant contributors to this condition.
Risk Factors and Frequency for Seborrheic Dermatitis
Seborrheic dermatitis (SD), a skin condition, affects about 5% of the global population. However, approximately 50% of people have a non-inflammatory variant of this condition, known as dandruff. SD affects all ethnic groups and appears in two main age groups: in the first three months of life and again between the onset of puberty and people in their forties. In Australian preschool children, about 72% had SD at three months, which dramatically reduced to an overall incidence of 10%. About 14% of middle-aged and elderly adults have SD, according to Rotterdam Study data analysis. In people with HIV-AIDS, the prevalence of SD is significantly higher, affecting 35% of those with early HIV infection and up to 85% of AIDS patients.
The chance of developing SD is influenced by several factors:
- Age
- Gender, with males being more affected
- Increased activity in the sebaceous glands, which are responsible for producing the skin’s oil
- Having an impaired immune system, seen in conditions like lymphoma, kidney transplantation, and HIV-AIDS
- Having neurological or psychiatric conditions, including Parkinson’s disease, stroke, Alzheimer’s disease, significant depression, and autonomic dysfunction
- Exposure to certain medications such as dopamine antagonists, immunosuppressants, psoralen (and psoralen along with ultraviolet A), and lithium
- Living in an environment with low humidity and cold temperatures
Signs and Symptoms of Seborrheic Dermatitis
Seborrheic dermatitis (SD) is a skin condition with lesions, or affected areas, most commonly appearing in parts where the skin has a lot of sebaceous (oil-producing) glands. These areas include the scalp and face. SD can present differently in infants (ISD) and adults (ASD). Individuals with ISD generally do not present symptoms, but often have coexisting conditions like atopic dermatitis. On the other hand, ASD often includes itching, particularly with scalp lesions, along with a burning sensation.
Characteristically, SD shows pinkish patches and plaques with a fine white scale and a yellow-ish crust, often described as a greasy scale crust. The condition may occur in one or more locations, with lesions usually having ill-defined boundaries.
- Pinkish patches and plaques
- Fine white scale
- Yellowish crust
The mildest form of SD often occurs on the scalp and beard region and is commonly called pityriasis capitis or sicca. This milder form is associated with shedding of small light-colored flakes of skin, or “dandruff”. A sudden severe onset of SD may suggest the presence of HIV-AIDS. Commonly, there is face reddening, scaling, and dandruff. Darker skin may show persistent coloring changes with areas of both decreased and increased coloring.
ASD commonly affects the face, scalp, and chest, and is usually symmetrical in the facial area, including the cheeks, center of the forehead, eyebrows, and external ear canal. Inflammation of the eyelid margins, or blepharitis, is common too.
ISD normally occurs in the second week after birth and lasts 4 to 6 months. Same as ASD, it can appear on areas where skin folds, such as the face, neck and under arms. The rash is typically neither itchy nor painful. However, it may distress parents due to its appearance. A common form of ISD called “cradle cap” refers to a yellow crusty scale that appears on the baby’s scalp.
Testing for Seborrheic Dermatitis
If you have severe seborrheic dermatitis (SD), a skin condition that typically causes flaky, scaly skin, your doctor may be quicker to test you for HIV, especially if your SD symptoms appeared suddenly. Similarly, if you’re an older patient, your doctor may check for signs of Parkinson’s disease, a brain disorder that can affect your movement. It’s also possible they will want to review any medications you’re currently taking.
Your doctor might perform several tests to help diagnose your skin condition and uncover any related issues. Here’s a list of potential tests:
- A potassium hydroxide (KOH) examination of skin scrapings: this can help detect skin fungi.
- A swab for microscopy, culture, and sensitivities: this is taken from your skin to look for infections under a microscope.
- Histology and direct immunofluorescence: these tests check skin tissue for signs of disease.
- HIV serology; Venereal Disease Research Laboratory (VDRL) test: these are blood tests to check for HIV or syphilis.
- Serum zinc levels: this checks the amount of zinc in your blood.
- Tests for Antinuclear antibodies (ANA), extractable nuclear antigens (ENA); erythrocyte sedimentation rate (ESR): these are blood tests that check your body’s immune response.
All these tests help your doctor better understand your condition and decide the best treatment for you.
Treatment Options for Seborrheic Dermatitis
Seborrheic Dermatitis (SD) treatment can vary based on the patient’s age and the extent and seriousness of the condition. One of the essential steps in managing this skin condition includes adopting good skin care practices. This includes using substitutes for regular soap and applying suitable moisturizers. Treatments not only address the actual disease but also target other symptoms like excessive skin scaling, bacterial infection, and any related symptoms, especially itching.
Medical experts from Denmark suggest using creams or lotions that fight fungal infections as the primary treatment. Steroid creams and medications called calcineurin inhibitors (which reduce inflammation and swelling) should only be used when the symptoms are severe or to manage significant flare-ups. For infants (ISD), it’s critical to gently remove the crust that forms on the scalp, commonly known as cradle cap, and to address any concerns the parents may have. Creams and a soft toothbrush can help soften and eliminate these scales. Meanwhile, for adult SD (ASD), alleviating itchiness and discomfort is vital.
Treatment typically includes antifungal, keratolytic (scale-removing), anti-itch, and anti-inflammatory (steroid creams and calcineurin inhibitors) medications. It may be more effective and cause fewer side effects to use different treatments in rotation rather than just sticking to one. For SD affecting your scalp and other areas, antifungal medications, as well as mild steroid creams, have proven to be effective. Also, using a mild steroid cream and an antifungal cream together intermittently has been shown to work well, but a stronger steroid cream may be necessary for short-term treatment of scalp ASD.
The use of shampoos containing ingredients that reduce itch and remove scales, along with others that kill bacteria and reduce inflammation, can be beneficial too. Applying the shampoo to the affected scalp and other non-scalp areas, then rinsing it off after 5 to 10 minutes could be a part of the treatment. However, using treatments like salicylic acid (for scale removal), selenium, or zinc should be done with caution in infants because information on their safety and effectiveness is lacking. However, the antifungal medication ketoconazole has been shown to be safe for use in infants.
To manage possible side effects associated with steroid creams, their intermittent use, or using preparations like 1% pimecrolimus cream (that can spare the need for steroids) is recommended. Utilizing the anti-inflammatory effect of antifungal creams is another strategy that is considered equivalent to the effect of 1% hydrocortisone.
If the disease is widespread or does not respond to topical treatments, oral medications can be an option. These medications may need careful monitoring for their possible effects on the liver and heart and interactions with other medications. However, these are helpful due to their antifungal and anti-inflammatory properties. It is recommended that an expert team review the potential use of oral treatments in infants due to a lack of safety and effectiveness data. For patients with HIV-AIDS, antiretroviral treatment frequently improves SD. Similarly, in patients with Parkinson’s disease, SD tends to improve with L-dopa therapy.
The future of SD treatments could be aimed at improving the skin’s protective barrier function or restoring the composition of lipids (fats) on the skin surface. A general treatment formulary, a list of preferred medications, can include various topical creams, lotions, shampoos, and oral medications.
What else can Seborrheic Dermatitis be?
When diagnosing Atopic Dermatitis (ASD), doctors consider a variety of skin conditions. These can actually manifest differently depending on the body area impacted, such as:
Scalp
- Psoriasis: Non-itchy, often found in the back and front of the scalp.
- Eczema: Can be a reaction to different hair care products.
- Darier disease: Characterized by clusters of yellow-brown rough bumps.
Face
- Psoriasis, Lupus, and Rosacea: These may sometimes occur with other symptoms such as pitted nails, skin atrophy, or skin redness.
- Acne: Exhibits skin bumps filled with pus.
- Eczema: A rash on the eyelids.
- Darier disease: Can also cause changes in the nails.
Trunk (torso)
- Psoriasis, Pityriasis, Lupus, and Eczema: These are characterized by red skin plaques, itching, and rashes.
- Tinea and Erythema: Look out for raised edges on the skin and expanding skin lesions.
- Darier and Grover diseases: Can manifest as greasy wart-like patches on the skin.
Intertriginous Areas (skin fold areas)
- Psoriasis and Dermatitis: Sharp borders and itching are key signs.
- Tinea, Erythrasma, and Candidiasis: Involve advancing borders, coral-red fluorescence, and small red bumps around a main rash (satellite lesions).
- Hailey-Hailey disease: Acanthosis is a characteristic sign of this condition.
There are also other differential diagnoses considered such as drug reactions, parapsoriasis, pemphigus foliaceus, and secondary syphilis.
For Infants’ Seborrheic Dermatitis (ISD), common differential diagnoses include:
Cradle Cap
- Tinea capitis: Identified by broken hairs or “black dots”.
- Impetigo: Characterized by yellow crusted sores.
Diaper Region
- Irritant contact dermatitis: Appears where the diaper rubs against the skin.
- Candidiasis: Might be due to yeast in fecal matter and is noticed due to small satellite lesions.
- Infantile psoriasis: Identified by sharply defined red patches.
- Histiocytosis X and Acrodermatitis Enteropathica: These conditions may tend to be confined to the skin folds.
What to expect with Seborrheic Dermatitis
ISD typically impacts the scalp and is usually mild and goes away on its own. However, ASD is a long-term skin condition that involves periods of worsening symptoms, followed by periods of improvement.
While ASD can’t be completely cured, it can be effectively managed. Even though this disease can negatively impact a patient’s quality of life, appropriate and timely treatment can greatly improve this, leading to a better day-to-day experience.
Possible Complications When Diagnosed with Seborrheic Dermatitis
Seborrheic dermatitis (SD) usually develops in a harmless way, and it’s very rare for serious complications to occur. Certain areas of the body where skin touches skin, and also the eyelids, are more likely to get secondary bacterial infections, particularly during severe flare-ups. The diaper area, in specific, tends to have excessive growth of a fungus called Candida.
In some rare cases, a condition called erythroderma is seen in infants with weaker immune systems who have a severe form of SD. This condition is generally more common in adults who have HIV-AIDS. However, it’s not completely certain if SD is directly responsible for causing erythroderma, as erythroderma is typically more prevalent in oily-part of skin. One of the major issues related to both infantile SD (ISD) and adult SD (ASD) is the misdiagnosis of the skin condition.
Common Issues Related to Seborrheic Dermatitis:
- Secondary bacterial infections in skin-contact areas and eyelids
- Excessive Candida growth in the diaper region
- Erythroderma in infants with weak immune system
- Misdiagnosis of the skin condition in both infants and adults
Preventing Seborrheic Dermatitis
Teaching parents about ISD (Inborn fault of Metabolism) can significantly reduce their worries related to the condition. Once they get the necessary information, they can confidently manage their condition.
For ASD (Autism Spectrum Disorder), it’s crucial to understand that there isn’t a cure, but the condition can be controlled and primarily managed at home. There are many ways to manage this condition effectively, providing a quality life for those diagnosed.
There are many treatments for SD (Sleep Disorders) that you can get without a doctor’s prescription. You can find these treatments over the counter at your local pharmacy or even on supermarket shelves. Guiding patients towards these products can save their time and reduce the costs related to doctor’s appointments.
