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What Causes Seborrheic Dermatitis

Seborrheic dermatitis is chronic prolonged inflammation in the skin and scalp that leads to patchy redness, itching and scaling, and common dandruff. It occurs in babies, teenagers, adults, and seniors. Our oldest patient with Seborrheic dermatitis was 102. So, what causes seborrheic dermatitis and how can you deal with the problem?

Seborrheic Dermatitis And The Immune System


The skin has many mechanisms known collectively as our Innate Immune System. When some of those mechanisms are not fully functioning, an overgrowth of microbes and yeast occurs. These can either directly or indirectly cause runaway inflammation in the skin that does not stop or “break.” 


Our entire immune system also has over 40 brake-like mechanisms for tamping down or putting the brakes on runaway inflammation. Each brake-like mechanism is established and regulated by its own particular set of genes that we inherit. If some of these aren’t fully functioning, we have runaway inflammation triggered or worsened by minimal yeast and microbe overgrowth on the skin. 


Seborrheic dermatitis is a ubiquitous and usually mild expression of these two phenomena.


Overgrowth of yeast known as Pityrosporum, aka Malassezia, is most often associated with causing flares and chronic persistence of Seborrheic dermatitis. In a few cases, Seborrheic dermatitis is not triggered by yeast and is independent of yeast overgrowth in the skin. When the elderly lose the ability to shampoo daily and clean their skin, they often develop severe Seborrheic dermatitis. Dead skin cells and oil accumulate, and the Malassezia breaks down the skin cells and the oils into irritating oils and debris. These agents directly stimulate the inflammatory aspects of our Immune System, causing itching, redness, and scaling to increase and persist.


Most of us do not have a perfect Innate Immune system and a perfect set of 41 brakes for preventing runaway inflammation. As a result, most of us, at different times of our lives, need things that help our Microbiome and help to tamp down runaway inflammation.


In Dr. Harlan’s opinion, no other product out there “goes directly after” Seborrheic dermatitis as SmartLotion® does. SmartLotion® also enhances and makes more effective all-prescription treatments for Seborrheic dermatitis. It can be added to any program for the skin.  

what causes seborrheic dermatitis

Seborrheic Dermatitis And Diagnosis


Seborrheic dermatitis is one of the most chronic conditions in all of Dermatology, and it’s usually poorly understood and often ignored by practitioners and providers. Many new patients already know they have Seborrheic dermatitis because it’s a chronic condition. However, they’ve never had a product that: “Directly went after their Seborrheic dermatitis” and controlled it well. It’s essential to see an experienced Dermatologist who can sort out Seborrheic dermatitis from Atopic dermatitis, Rosacea, and mild forms of Psoriasis. If you have one of these conditions on the face or in sensitive skin folds on the body, SmartLotion® will work on all of them. These conditions can cause patchy redness and scaling, and all of them will respond to SmartLotion®. It’s essential to understand a few things about these other conditions when they are causing patchy Seborrheic dermatitis-like redness and scaling in the scalp, face, or body.


  • Psoriasis will tend to be more resistant to therapies and often require two or three weeks of prescription-strength topical steroids occasionally to help maintain control. 
  • Atopic dermatitis (eczema) will tend to have more itching and burning and often have an intolerance to lotions and creams with stinging that require extra measures, as found in our Experience Guide. In young people and teenagers, Atopic dermatitis can exactly mimic Seborrheic dermatitis or be present along with Seborrheic dermatitis. Atopic dermatitis patients are more likely to have co-existent allergies to cats, mold, pollens, metals like gold and nickel in silver and white gold, and a preservative known as Methylchloroisothiazolinone in shampoos, washes, and conditioners. 
  • Rosacea. This condition usually occurs on the face with patchy or diffuse redness and has very little scaliness. But it can have scaliness when the Rosacea is associated with barrier problems and stinging. Fortunately, nothing is better for these patients than adding SmartLotion® to their Rosacea program. 


Additional Supportive Treatments

Medicated shampoos are essential for healthy skin and scalps and for preventing Seborrheic dermatitis flares. In addition, a microscopic yeast called Pityrosporum, aka Malassezia, lives to some degree on everyone’s skin and hair. 


Babies with immature immune systems can have an overgrowth of this yeast, contributing to neonatal Seborrheic dermatitis. NSD is usually limited to scaling scalp called “cradle cap.” However, sometimes it’s severe with extensive bright red erythema on the baby’s face, neck, and body creases. Bathing with gentle baby shampoos and body washes is essential. 


Almost nothing is FDA approved for children under 2, but Dr. Harlan allows parents to use SmartLotion® to loosen scalp scale for two weeks at a time in treating cradle cap. In addition, he enables parents to alternate Aveeno Eczema Formula moisturizing lotion with SmartLotion® for itching and redness associated with the face and body version of infant Seborrheic dermatitis because he considers it safer than OTC Hydrocortisone creams. 


SmartLotion® is used in a limited and conservative way in Infant Seborrheic dermatitis for short periods.


For teenagers and adults with Seborrheic dermatitis, his patients use it for years as both a rescue from flare-ups and a prevention product for chronic Seborrheic dermatitis.


Zinc-containing shampoos are often the first-line therapy for scaly scalps, eyebrows, mustaches, and beards for teenagers and adults. Dr. Harlan likes DHS Zinc shampoo because it’s free of Methylisothiazolinone, but most people tolerate Head & Shoulders with Zinc. Creams and lotions are the main treatments for seborrheic dermatitis. Medicated shampoos often work better when they are combined and alternated. Ketoconazole shampoo is an excellent additional medicated shampoo to use, alternating with a zinc pyrithione shampoo. Ketoconazole is an antifungal antibiotic shampoo for reducing Malassezia yeast growing in the hair and on the skin.


Occasionally there is a component of Psoriasis causing scalp itching and scaling and alternating with a Tar shampoo. Like sulfur, refined tar derivatives were used for centuries to treat inflammation and itching skin conditions before topical steroids were invented in the 1960s. T/Gel® and many other Tar shampoos are available. Tar products can make the skin more sensitive to sunburn when not rinsed away well. 

T/Sal® and shampoos like it contain 3% Salicylic acid that gently exfoliates away dead skin cells and scales that tend to be loaded with yeast and microbes.


Taking Seborrheic Dermatitis Support Further


Some people do the best when Selenium Sulfide shampoo, like Selsun Blue, is part of their home grooming and skin care program. But, most importantly, they do well when they shampoo regularly. 

Shampoos with topical steroids are prescription-based, and they are popular when treating difficult itching from Atopic dermatitis and stubborn Psoriasis. They are usually not needed for scalp Seborrheic dermatitis.

Mayo Clinic, on its website, allows patients to “home remedy” with OTC hydrocortisone cream for Seborrheic dermatitis for a limited time. However, Dr. Harlan feels that SmartLotion® is safer and far more effective. SmartLotion® is also more effective when used with the antifungal cream version of Ketoconazole for facial Seborrheic dermatitis.  


SmartLotion® Eyelash Care


Other grooming tips include cleansing scaly eyelashes. Use warm water and tear-free baby shampoo to clean the eyelashes at least twice a week gently. SmartLotion® can be used for short periods, in small amounts, directly on the lashes or the eyelids. Patients with Glaucoma should not use this strategy. Dr. Harlan often allows patients who do not have Glaucoma to use SmartLotion® three times weekly to prevent atopic dermatitis from flaring on the eyelids. A non-steroid medication like Elidel (pimecrolimus) cream is safe for long-term use for Atopic dermatitis of the eyelids. It’s essential to see a dermatologist with experience in patch testing for allergies. Many eyelid rashes are caused by allergies to droplet medication, metals, cats, fragrances, or anything the hands bring to the face. Cat allergies affecting the eyelids may have a falsely negative allergy test at the Allergy Clinic, yet it’s still the cat. Being away from the cat is the only way to know.


Our blog is full of valuable articles about eczema and the management of its symptoms. For those who worry about TSW (topical steroid withdrawal), please read our TSW article that goes into depth about the risks of TSW and how SmartLotion is TSW safe long term. If you have any questions about SmartLotion, please don’t hesitate to contact us.




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