Table 2.

Evaluation of the microbiome as clinical biomarker for each dermatological disease included in the review based on the criteria of a useful biomarker as defined by de Visser et al. 4

Indication	Manuscripts (N)	Evidence level overall	Consistency	Therapeutic response	Dose–response relation	Relationship with disease	Recommendation for trial implementation
PV	10	Low	–	0	0	0	Negative, more evidence needed
HS	2	Low	+	0	0	+	Negative, more evidence needed
UC	10	Low	+	0	0	+	Negative, more evidence needed
SD	4	Low	–	0	0	+	Negative, more evidence needed
AV	5	Moderate	+	+	0	+	Positive
AD	11	Moderate	+	+	0	+	Positive

AD, atopic dermatitis; AV, acne vulgaris; HS, hidradenitis suppurativa; PV, psoriasis vulgaris; SD/PC, seborrhoeic dermatitis/pityriasis capitis; UC, ulcus cruris

Scoring system indicated as follows: +, studies in general report a positive outcome; 0, no studies available; –, studies in general report a negative outcome