Probiotics: A natural solution to atopic dermatitis?

The atopic dermatitis is a chronic inflammatory condition characterised by itchy, red and scaly lesions often located on the body's flexion surfaces. Several solutions exist to alleviate eczema flare-ups, including the application of corticosteroids, anti-inflammatory drugs. Very common in children, atopic dermatitis results from a dysfunction of the skin barrier due to a mutation in the gene coding for filaggrin, a structural protein of the epidermis.

Beyond this genetic component, studies have shown that the skin microbiota and its balance also play a role in the pathogenesis of atopic dermatitis. Indeed, it has recently been highlighted that the proportion of Staphylococcus aureus, bacteria naturally present in the skin flora, drastically increases during eczema flare-ups. Furthermore, researchers believe that the lipophilic yeast Malassezia is linked to atopic dermatitis and contributes to exacerbating skin inflammation. Additionally, it is suggested that intestinal dysbiosis may be linked to atopic dermatitis. Indeed, a study involving 132 patients showed that the enrichment of the intestinal flora with Faecalibacterium prausnitzii could be correlated with atopic eczema.

Although the precise role of microorganisms in the development of atopic dermatitis is still poorly understood, it appears that an imbalance in the skin and/or gut microbiota may be linked to this skin condition.

Probiotics are microorganisms external to the body that, when consumed in adequate amounts, have a beneficial effect on health. Due to their numerous benefits for the skin, it is estimated that the global probiotics industry is growing at a rate of 15 to 20% per year. In addition to their moisturizing, antioxidant, and firming cosmetic properties, probiotics have a real therapeutic interest and can greatly improve symptoms related to dermatoses such as acne or atopic dermatitis.

A recent double-blind, placebo-controlled study tested a lotion containing 5% of Vitreoscilla filiformis. 75 volunteers suffering from atopic dermatitis applied this lotion or a placebo twice a day for 30 days. The severity of the disease was then assessed using the SCORAD (Scoring Atopic Dermatitis), a tool that takes into account the severity of lesions, the intensity of itching, and the impact of the disease on sleep, daily activities, and mood. The transepidermal water loss and itching were reduced. Furthermore, a reduction in skin colonisation by S. aureus was observed.

Further studies led by DRAGO involved 4538 patients suffering from atopic dermatitis, randomly divided into two groups. The first group received a treatment with the probiotic Lactobacillus salivarius at a dose of 10,000 CFU/µg in maltodextrin, and the second group received a placebo, consisting only of maltodextrin. These tablets were consumed twice a day for 16 weeks. After four months, a significant reduction in SCORAD was observed only in the group treated with the probiotic, and no adverse effects were noted during the study.

Some researchers have demonstrated a reduction in inflammatory mechanisms and a reconstruction of the skin barrier following the topical use of Lactobacillus paracasei. These effects are beneficial in cases of atopic dermatitis, a condition strongly linked to skin inflammation and a fragile epidermis. Furthermore, in vitro studies have shown that this probiotic also has inhibitory effects on the growth of S. aureus and Cutibacterium acnes, a bacterium involved in the pathogenesis of acne.

Conclusion : Despite the increasing number of research on this topic, the use of probiotics to combat atopic dermatitis is still recent. In order to ensure a safe and effective use of these microorganisms, further in-depth studies still need to be conducted to prove the real benefits of their use and ensure that the benefits/risks balance is in their favour.

• GUENICHE A. & al. Effects of nonpathogenic gram-negative bacterium Vitreoscilla filiformis lysate on atopic dermatitis: a prospective, randomized, double-blind, placebo-controlled clinical study. The British Journal of Dermatology (2008).

• SEGRE J. & al. Temporal changes in the skin microbiome linked with disease outbreaks and treatment in children with atopic dermatitis. Genome research (2012).

• DRAGO L. & co. Alteration of faecal flora and clinical impact of L. salivarius LS01 in adults with atopic dermatitis. Journal of Clinical Gastroenterology (2012).

• PARK Y. H. & co. Probiotics and Atopic Dermatitis: A Synopsis. Frontiers in Microbiology (2016).

• SUYENAGA E. & al. An exploration of the potential application of probiotics in the treatment of skin conditions: acne and atopic dermatitis. International Journal of Dermatology (2018).