Seborrheic Dermatitis and Psoriasis: A Journey into the Depths of Inflammation

"Chronic skin conditions are often not just a diagnosis, but a silent reflection of other problems the body is experiencing deeper within."
– Pharmacist Berfin Işık

1. Sounds of Chronic Inflammation on the Skin

Seborrheic dermatitis, fungal acne, and psoriasis are chronic skin conditions characterized by flare-ups, and often their common source is not immediately apparent. All are linked to the immune system, but they progress through different mechanisms.

• Seborrheic dermatitis is often triggered by an overgrowth of yeasts of the Malassezia species.
• Psoriasis is an autoimmune process characterized by the overly rapid renewal of skin cells, resulting in scaling and plaque formation.

Recent studies, particularly in recent years, have shown that these types of chronic inflammatory skin diseases are not solely skin-specific problems, but are closely related to disruption of the gut microbiota . An unbalanced gut flora can trigger processes such as leaky gut, hyperactivity in the immune system, and systemic inflammation, paving the way for reactions such as seborrheic dermatitis or psoriasis on the skin. Therefore, simultaneously implementing topical applications to the skin surface along with support targeting the root cause, namely the gut microbiota, can lead to much more effective and lasting results in the treatment process.

The gut microbiome is nourished by far more vitamins, minerals, and elements than we realize. Immunity is directly related to the health of the gut microbiome. The foundation of a functional and holistic approach begins with replacing what is lacking in the body; relying solely on topical applications without supplementing the body with the necessary nutrients in appropriate doses will alleviate symptoms but will be insufficient to prevent flare-ups. Certain vitamins and minerals are vital for the proper functioning of the system. Maintaining normal levels of vitamin D, ferritin, intracellular magnesium, intracellular zinc, vitamin B12, and omega-3 is cornerstone in the treatment of chronic skin conditions and autoimmune symptoms.

2. Fungal Effect in Seborrheic Dermatitis: Malassezia

One of the most common triggers for seborrheic dermatitis and fungal acne is the overgrowth of Malassezia fungi, which are found in the skin's natural microbiota. These yeasts:

• They are sebum-dependent, feeding on almost all oils, including the skin's own sebum.
• They break down fatty acids with lipase enzymes, creating inflammatory free fatty acids.
• They weaken the skin barrier and create itchy, scaly areas.

The flare-ups typically occur in sebum-rich areas such as the scalp, inside/behind the ears, sides of the nose, between the eyebrows, at the base of the eyebrows, and the middle of both breasts . Its appearance, similar to classic acne, often leads to confusion with bacterial acne, but a detailed examination by a specialist should not be too difficult to distinguish.

3. Things to Consider When Choosing a Product

Ingredients to Avoid (For Seborrheic Skin)

• Sterol-based oils (e.g., lanolin)
• Cocoa glycerides
• Paraffin derivatives
• Strong perfumes and essential oils (can trigger Malassezia)
• Long-chain fatty acids
• Fermented ingredients (bifida, kombucha, etc.)

Content that should be preferred

• Sebum balancers: Niacinamide, Zinc PCA, L-carnitine
• Sedatives: Panthenol, Allantoin, Madecassoside
• Antifungal: Piroctone olamine, Climbazole, Undecylenic acid
• Barrier enhancers: Niacinamide, Ectoin, Beta-glucan

📌 Note: The oat-based beta-glucan used in L'Adore Tokyo formulations is a safe option for skin prone to fungal acne.

4. Topical & Oral Probiotics & Prebiotics

Topical

• Prebiotic ingredients: Nourish the skin's beneficial bacteria and maintain microbiota balance.
• Postbiotic extracts: Fermented ingredients strengthen the barrier.
• While oral probiotic use yields positive results in individuals with seborrheic dermatitis, the same probiotic ingredients can be triggers when applied topically. This is primarily due to the fact that the gut microbiome and the skin microbiome are nourished by quite different bacterial populations; furthermore, the skin microbiome has a higher tolerance to prebiotic and postbiotic extracts.

Oral

• Lactobacillus rhamnosus GG, L. paracasei, and Bifidobacterium breve are examples of beneficial bacteria that help suppress skin inflammation and provide powerful support from the inside out by repairing the gut microbiome in individuals with a history of seborrhea and psoriasis.

🔬 Clinical data: Navarro-Lopez et al. (2021) showed that probiotic supplementation reduced itching and rash in individuals with seborrheic dermatitis over an 8-week period.

5. Food Supplements, Functional Supplements, and Nutritional Recommendations

Skin health is not only determined by externally applied topical products, but also by internal support . In chronic inflammatory skin conditions such as seborrheic dermatitis and psoriasis, nutrition and gut health have a direct impact on healing.

🧠 Oral Supplements Based on Clinical Findings

• Zinc Carnosine: Provides both sebum regulation and anti-inflammatory properties, and is a nutrient source for the gut microbiome. (Del Rosso, 2020)

• L-Glutamine: Reduces systemic inflammation and balances the immune system.

🔬 Clinical observations show that glutamine supplementation can improve symptoms such as itching, redness, and scaling.

• Vitamin B6 : Plays a role in fat metabolism.

• Biotin : Supports epidermal integrity.

• Omega-3 (EPA/DHA): Can reduce redness, itching, and lesions by suppressing inflammatory markers such as TNF-α and IL-6.

• Vitamin D3 : It has an autoimmune balancing effect, especially in patients with psoriasis.

• Sulfur compounds (MSM, NAC) : Support liver detoxification pathways, thereby reducing skin burden.

🧪 Prebiotic and Probiotic Supplements (Oral Intake)

• Strains such as Lactobacillus rhamnosus GG, L. paracasei, and Bifidobacterium breve can reduce inflammation in individuals with seborrheic dermatitis and psoriasis by lowering IL-1β and TNF-α levels.

🔬 Clinical data: Navarro-Lopez et al. (2021), In the study, individuals with seborrheic dermatitis who were given probiotic supplements experienced a significant reduction in itching, erythema, and rash.

🥣 Functional Foods and Fermented Foods

• Homemade kefir and yogurt: With their probiotic content, they support the balance of the microbiota. Although considered dairy products, their fermentation process nourishes the microbiota and increases the population of beneficial bacteria.

• Pickles (homemade, brine-based instead of vinegar) : Rich in lactic acid bacteria.

• Miso, tempeh, kimchi : Fermented Asian products provide postbiotics that regulate immunity.

• Whole grains and fiber-rich vegetables: With their prebiotic fiber content, including inulin and fructooligosaccharides, they are a food source for beneficial bacteria.

In addition, an anti-inflammatory diet that eliminates dairy products, sugar, and gluten derivatives will provide significant support in managing attacks.

Recommendation: Especially for individuals undergoing an antifungal diet for seborrheic dermatitis symptoms, it is recommended to avoid commercially produced yeast products (baker's yeast, brewer's yeast) and to prefer naturally fermented, low-histamine products.

🌿 Prebiotic/Probiotic Ingredients in Dermocosmetics

• Prebiotic actives (inulin, alpha-glucan oligosaccharide): Support the colonization of beneficial microorganisms on the skin surface.

• Fermented extracts (Lactobacillus lysate, Bifida ferment lysate): Strengthen the skin barrier and soothe redness. Requires short-term and controlled use.

📌 Providing microbiota support from both internal and external sources is one of the most effective strategies for barrier integrity and symptom control in chronic inflammatory skin diseases, although not necessarily in seborrheic-prone skin.

6. Psoriasis: A Brief Overview

Psoriasis is caused by the immune system sending incorrect signals to the skin. An disproportionate population of the Malassezia fungus on the skin also contributes to the process.

Symptom	Explanation
Plaque and Flaking	Thick, silvery scales
Itching or Burning	It is caused by the action of inflammatory cytokines.
Nail and joint involvement	It can be seen in systemic psoriasis.

Goals in supportive care:

• Initiating barrier repair by disabling the triggers.

• To soothe inflammation.

• Balancing the cell cycle

7. Final Words

Seborrheic dermatitis and psoriasis are not just "skin problems," but represent chronic conditions resulting from an imbalance in the skin-microbiota-immune system. Supporting your skin not only from the outside but also from the inside; proceeding with the right ingredients, supplements, and medical support when necessary, is the key to a long-term solution.

Source

• Kim, J., Lee, J., & Park, S. (2022). Efficacy of piroctone olamine shampoo in the treatment of seborrheic dermatitis. Journal of Dermatological Science, 105(2), 95–101. https://doi.org/10.1016/j.jdermsci.2022.04.002

• Navarro-Lopez, V., et al. (2021). Effect of oral probiotics on seborrheic dermatitis: A randomized clinical trial. Clinical, Cosmetic and Investigational Dermatology, 14, 789–797. https://doi.org/10.2147/CCID.S312064

• Del Rosso, J. Q. (2020). The role of zinc and niacinamide in inflammatory skin disorders. Journal of Clinical Aesthetic Dermatology , 13(5), 14–21.