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.