Table 2.

Characteristics of 17 studies using single-strain probiotic lactobacilli with the outcome measure of SCORAD index.

Reference (First Author, Year)	Population That Completed Trial	Intervention of Single-Strain Probiotic Lactobacilli		Main Findings
		Probiotic/Dosage	Duration
Isolauri 2000 [41]	In this study, 27 patients, mean age 4.6 months, with atopic disease symptoms, divided into three equal groups. A total of 9 in two probiotic groups (Group 2: not lactobacilli) and 9 in the placebo group.	Lacticaseibacillus 1 rhamnosus GG (LGG), 3 × 108 cfu/g	2 months	A statistically significant decrease in the SCORAD index was found in both probiotic groups compared to the placebo. Both probiotics also counteracted inflammatory responses compared to the placebo (CD4 levels were statistically significantly lower in the probiotic group compared to the placebo).
Kirjavainen 2003 [42]	In this study, 35 patients, mean age 5.5 months, with atopic disease symptoms, divided into three groups. A total of 14 in group one, 13 in group two (heat-killed LGG) and 8 in the placebo group.	Lacticaseibacillus rhamnosus GG, 1 × 109 cfu, qd	7.5 weeks	The decrease in the SCORAD index within the viable LGG group tended to be greater than within the placebo group. The treatment with heat-inactivated LGG was associated with adverse gastrointestinal symptoms and diarrhea.
Viljanen 2005 [43]	In this study, 230 patients aged 1–12 months with atopic eczema–dermatitis syndrome, divided into three groups. A total of 80 in probiotic group 1, 76 in group 2 (multi-strain) and 74 in the placebo group.	Lacticaseibacillus rhamnosus GG, 5 × 109 cfu, qd	4 weeks	No statistically significant effects of probiotic supplementation on mean SCORAD index reduction between groups were found. A statistically significant lower SCORAD index was observed in Ig-E sensitized infants after supplementation in the probiotic group compared to placebo.
Weston 2005 [44]	In this study, 56 patients aged 6–18 months with moderate to severe AD. A total of 26 in the probiotic group and 27 in the placebo group.	Limosilactobacillus 1 fermentum VRI-033 PCC, 1 × 109 cfu, bid	8 weeks	A statistically significant lower SCORAD index was observed after supplementation in the probiotic group compared to the placebo. The reduction in the SCORAD index over time was significant in the probiotic group but not in the placebo group.
Brouwer 2006 [45]	In this study, 50 patients aged 1–5 months with AD, divided into three groups. A total of 33 in both single-strain probiotic lactobacilli groups (16 in group 1 and 17 in group 2) and 17 in the placebo group.	Lacticaseibacillus rhamnosus GG, 5 × 109 cfu/g	3 months	There were no statistically significant effects of probiotic supplementation on SCORAD, sensitization, inflammatory parameters or cytokine production between groups.
		Lacticaseibacillus rhamnosus, 5 × 109 cfu/g
Fölster-Holst 2006 [46]	In this study, 42 patients aged 1–55 months with moderate to severe AD. A total of 21 in both the probiotic and placebo group.	Lacticaseibacillus rhamnosus GG, 1 × 1010 cfu, qd	8 weeks	No significant differences were observed between the groups with respect to the SCORAD index. No significant differences were observed between the groups with respect to other clinical symptoms (pruritus, sleep loss), the use of topical corticosteroids and antihistamines or immunological parameters.
Grüber 2007 [47]	In this study, 102 patients aged 3–12 months with mild to moderate AD. A total of 54 in the probiotic group and 48 in the placebo group.	Lacticaseibacillus rhamnosus GG, 5 × 109 cfu, bid	12 weeks	No significant differences were observed for the SCORAD index, use of rescue medicine or increase in mean total logarithmic serum immunoglobin E after supplementation in the probiotic group compared to placebo. When stratified for age, eczema severity or use of rescue medication, no statistically significant group differences in improvement were found.
Woo 2010 [48]	In this study, 75 patients aged 2–10 years with eczema–dermatitis syndrome. A total of 41 in the probiotic group and 43 in the placebo group.	Latilactobacillus 1 sakei KCTC 10755BP, 5 × 109 cfu, bid	12 weeks	Statistically significant lower SCORAD index, mean disease activity, proportions of patients achieving improvement and serum chemokine levels were observed after supplementation in the probiotic group compared to placebo.
Klewicka 2011 [49]	In this study, 40 patients aged 6–18 months with medium to severe AD. A total of 18 in the probiotic group and 22 in the placebo group.	Lacticaseibacillus casei DN-114001, 1 × 109 cfu, qd	3 months	A decrease in the SCORAD index was observed in the probiotic group. Supplementation with probiotics positively affected their gut microbiota.
Gore 2012 [50]	In this study, 133 patients aged 3–6 months with AD. A total of 43 in probiotic group I, 44 in probiotic group II (not lactobacilli) and 46 in the placebo group.	Lacticaseibacillus 1 paracasei CNCM I-2116, 1 × 1010 cfu, qd	12 weeks	No significant differences were observed for the SCORAD index after supplementation in the probiotic group compared to the placebo. Results were similar when the analysis was controlled for allergen-sensitization or when only sensitized infants were analyzed.
Han 2012 [51]	In this study, 83 patients aged 1–13 years with AD. A total of 44 in the probiotic group and 39 in the placebo group.	Lactiplantibacillus 1 plantarum CJLP133, 5 × 109 cfu, bid	12 weeks	Statistically significant mean changes in SCORAD index and lower SCORAD index, eosinophil counts, and logarithmic interferon-gamma and interleukin-4 were observed after supplementation in the probiotic group compared to placebo.
Wang 2015 [52]	In this study, 212 patients aged 1–18 years with AD and positive skin prick test, divided into 4 groups. A total of 159 in 3 probiotic groups with 55 in group 1 (single-strain), 53 in group 2 (single-strain), 51 in group 3 (both strains) and 53 in the placebo group.	Lacticaseibacillus paracasei GMNL-133 (Lp), 2 × 109 cfu, qd	3 months	A statistically significant lower SCORAD index and interleukin-4 levels were observed after supplementation in all three probiotic groups compared to the placebo.
		Limosilactobacillus fermentum GM090 (Lf), 2 × 109 cfu, qd
Prakoeswa 2017 [53]	In this study, 22 patients aged 0–14 years with mild and moderate AD. A total of 12 in the probiotic group and 10 in the placebo group.	Lactiplantibacillus plantarum IS-10506, 1 × 1010 cfu, qd	12 weeks	A statistically significant lower SCORAD index and levels of interleukin-4, interferon-gamma and interleukin-17 levels were observed after supplementation in the probiotic group compared to the placebo. The ratio of forkhead box P3 to interleukin-10 was significantly higher after supplementation in the probiotic group than in the placebo group.
Wu 2017 [54]	In this study, 62 patients aged 4–48 months with AD. A total of 30 in the probiotic group and 32 in the placebo group.	Lacticaseibacillus rhamnosus MP108, 1 capsule 2, qd	8 weeks	A statistically significant lower SCORAD index was observed after supplementation in the probiotic group compared to the placebo. Mean changes from baseline declined in the probiotic and placebo groups, but no statistically significant differences were noted.
Ahn 2020 [55]	In this study, 82 patients aged 2–13 years with mild to moderate AD. A total of 41 in each group.	Lactiplantibacillus pentosus 3, 1 × 1010 cfu, bid	12 weeks	No significant difference was found in the reduction in the SCORAD index after supplementation in the probiotic group compared to the placebo. However, a statistically significant reduction in the SCORAD index was observed in the subgroup of Immunoglobulin E-sensitized AD compared to placebo.
Rather 2021 [56]	In this study, 58 patients aged 3–18 years with mild to moderate AD divided into three groups. A total of 16 in the probiotic group, 22 in group II (received dead cells) and 20 in the placebo group.	Latilactobacillus sakei proBio65, 1010 cfu, qd	12 weeks	A statistically significant lower SCORAD total index was observed after supplementation in the probiotic group and the group receiving non-viable cells compared to the placebo. Statistically significant increase in skin sebum in the probiotic group as well as in the group that received non-viable cells.
Carucci 2022 [57]	In this study, 91 patients aged 6–36 months with AD. A total of 46 in probiotic group A and 45 in the placebo group.	Lacticaseibacillus rhamnosus GG, 1010 cfu, qd	12 weeks	A statistically significant higher rate of participants in the probiotic group after supplementation achieved the minimum clinically important difference in the SCORAD index compared to the placebo. The probiotic group also observed a beneficial modulation of the gut and skin microbiome.

Bid: Twice per day; qd: once per day; ¹ new nomenclature [12]; ² cfu not reported; ³ strain not reported.