Effectiveness of steroid injection for hand psoriatic dactylitis: results from a multicentre prospective observational study

Objective: To assess the effectiveness of steroid injection (local treatment, LT) into the digital flexor tendon sheath of dactylitis in psoriatic arthritis (PsA) patients as compared with systemic treatment (ST). Methods: Forty-six PsA patients with a total of 73 dactylitic fingers were assessed in an observational, multicentre, prospective study by the Leeds Dactylitis Index basic (LDI-b) score and evaluated for local pain (visual analogue scale-VAS pain) and functional impairment (VAS-FI). Steroid injection was proposed to all patients. Patients refusing LT were treated with oral NSAIDs. Both the groups continued baseline csDMARDs and/or corticosteroids therapy. The clinical outcomes were measured at baseline, 1 month (T1) and 3 months (T3). Results: The reduction of VAS-pain, VAS-FI and LDI-b values was statistically significant higher in the LT group (24 patients, 38 dactylitic fingers) as compared with the ST group (22 patients, 35 dactylitic fingers), both at T1 (p < 0.001, p < 0.001 and p = 0.008, respectively) and at T3 (p < 0.001, p < 0.001 and p < 0.001, respectively). A clinically meaningful treatment response (defined as a contemporary reduction of at least 5 points in VAS-pain and VAS-FI or as values of VAS-pain and VAS-FI were both ≤ 2) was observed at T1 in 33 (87%) digits in LT group and in 6 (17%) digits in ST group (p < 0.001). At T3, clinical response improved significantly in both the groups, with significant difference (94% vs 31%, p < 0.001). Conclusions: For the first time, we show the effectiveness of steroid injection into the digital flexor tendon sheath in improving clinical aspects of hand psoriatic dactylitis.Key Points• Therapy with steroid injection (local treatment, LT), into the digital flexor tendon sheath for the treatment of active dactylitis in psoriatic arthritis patients, is more effective when compared with systemic treatment (ST) alone.• The reduction of VAS-pain, VAS-functional impairment (VAS-FI) and Leeds Dactylitis Index basic values was statistically significant higher in the LT group as compared with the ST group, both at T1and at T3.• A clinically meaningful response was observed at T1 in 87% of digits of patients treated with steroid injection and in 17% of digits of the systemic treatment group (p < 0.001). At T3, clinical response improved significantly in both the groups, with significant difference.• For the first time, findings from this study show that the use of steroid injections into the digital flexor tendon sheath for psoriatic dactylitis could be an effective and safe first-line therapy for psoriatic dactylitis.