Ref. number Study populations’ characteristics/inclusion criteria Age (years) Sex F/M Clinical forms of skin psoriasis included Psoriatic arthritis (PsA) PASI (0–72) Nail psoriasis Treatment [27 ] N/A N/A Psoriatic patients; not further clarified N/A N/A N/A Untreated topically and systematically ≥14 days before enrolment [28 ] Mean ± SD: 40.2 ± 17.4 Range: 6.0–72.0 31/29 Plaque psoriasis 83.3%, guttate 10.0%, flexural 3.3%, pustular 1.6%, palmoplantar 1.6% Present in 23.3% PASI 25: 76.6% PASI > 25: 23.3% N/A Untreated topically ≥2 weeks before enrolment Untreated systematically ≥6 weeks before enrolment [29 ] Mean ± SD: 35.0 ± 15.5 Range: 7.0–79.0 12/18 Plaque psoriasis Excluded Mean ± SD: 9.3 ± 8.15 Range: 1.5–33.3 N/A Untreated topically and systematically ≥2 months before enrolment [30 ] Mean: 38.0 Range: 18.0–77.0 20/35 Psoriatic patients; not further clarified N/A Mean ± SD: 21.7 ± 8.3 N/A N/A (treatment before enrolment) [31 ] N/A N/A Plaque psoriasis: 9/12 Guttate psoriasis: 2/12 Erythrodermic psoriasis: 1/12 N/A N/A N/A 10/12 untreated at the time of enrolment 2/12 on methotrexate [32 ]* Median: 52.5 Range: 18.0–81.0 25/12 Plaque psoriasis N/A Median: 11.4 Range 3.5–42.0 N/A N/A [33 ] N/A 14/31 Plaque psoriasis N/A N/A N/A N/A [34 ] Mean ± SD: 47.5 ± 7.6 Range: 25.0–72.0 41/81 Psoriasis vulgaris: 102/122 Guttate psoriasis: 7/122 Erythrodermic psoriasis: 5/122 Present in 8/122 Mean ± SD: 7.3 ± 4.2 Range: 0.7–32.3 N/A Treated, untreated, well-controlled, and poorly controlled cases. Treatments: topical steroid, topical vitamin D3, psoralen ultraviolet A, and systemic treatments (etretinate, ciclosporin) [35 ] Stable, plaque type psoriasis: Mean: 50.0 Range: 24.0–85.0 Highly active psoriasis: Mean: 47.7 Range: 27.0–76.0 Acute guttate psoriasis: Mean: 31.3 Range: 18.0–49.0 N/A Stable, plaque type psoriasis: 16/52 Highly active psoriasis: 22/52 Acute guttate psoriasis: 14/52 N/A N/A N/A None of the patients received local nor systemic antipsoriatic treatment prior to the study [36 ] Mean ± SD: 34.5 ± 13.3 Range: 15.0–65.0 13/17 Psoriasis vulgaris: 90%; 10% not clarified 4/30: joint complaints 1/4: showed radiological evidence of PsA N/A N/A N/A [37 ] Mean: 47.0 Range: 21.0–64.0 4/10 Psoriasis vulgaris Excluded Mean: 8.5 Range: 2.0–25.3 N/A Untreated, topically and systematically ≥4 weeks before enrolment [38 ] Median: 52.5 Range: 15.0–82.0 19/1 Plaque psoriasis: 18/20 Suberythrodermic psoriasis: 1/20 Pustular psoriasis: 1/20 N/A Median: 11.4 Range: 3.0–40.5 N/A Untreated topically and systematically ≥10 days before enrolment [39 ] Mean ± SD: 40.6 ± 13.6 34/36 Plaque psoriasis: 30/70 Guttate psoriasis: 20/70 Pustular psoriasis: 20/70 N/A Mean ± SD: 6.6 ± 5.4 N/A Newly diagnosed or without systemic treatment ≥2 months before enrolment [40 ] Mean ± SD: 45.6 ± 13.2 Range: 18.0–69.0 10/50 Psoriatic patients; not further clarified N/A Mean ± SD: 15.7 ± 9.7 Range: 4.8–64.2 N/A N/A [41 ] Mean ± SD: 43.8 ± 15.1 Range: 18.0–71.0 21/27 Psoriatic patients; not further clarified N/A N/A N/A Untreated topically and systematically ≥4 weeks before enrolment Our study Mean ± SD: 44.5 ± 15.6 23/9 Active, chronic plaque psoriasis Excluded Median: 4.1 Range: 2.2–15.0 Excluded Untreated topically and systematically ≥1 year before enrolment