The objective of this multicentric, randomized controlled double-blind clinical trial is to demonstrate the efficacy of transdermal application of capsaicin in patients with painful digital osteoarthritis with a neuropathic pain component.

Participants will receive either a transdermal patch of capsaicin 179 mg (8%) or the control treatment (capsaicin 0.04%).

Researchers will compare the intensity of pain in the fingers at day 60 in the capsaicin 8% group versus capsaicin 0.04% (control arm)

Visit 0 : Screening visit (D0 - 30 days): Screen for eligibility

Visit 1 :Inclusion visit (D0): Randomization and blinded patch application of capsaicin 8% or 0.04%

Visit 2: Follow-up visit 1 (D60 + 7 days): Assessment +/- Patch renewal. Patients with finger pain still greater than 4/10 may receive an open application of a capsaicin 8%

Visit 3:Follow-up visit 2 (D120 +/- 7 days): Final assessment.

For the duration of the study, the patient will record in a notebook: analgesics, anti-inflammatories, corticoids and daily hand pain VAS.

Blood samples will be taken at V1 and V2 for subsequent measurement of pro-inflammatory cytokines (IL6, IL8, TNFa) and markers of cartilage degradation, in order to build up a serum library.

Inclusion Criteria:

• Diagnosis of digital osteoarthritis fulfilling the American College of Rheumatology criteria;
• Presence of finger pain of ≥ 40 mm on a visual analogue scale (VAS);
• Presence of finger pain with a neuropathic pain component (DN4 score ≥ 4/10)
• Inadequate response, adverse reactions, and/or contraindications to conventional analgesics and NSAIDs;

Exclusion Criteria:

• Patient with isolated rhizarthrosis;
• Patient with other joint disease affecting the fingers (gout, chondrocalcinosis, RA, spondyloarthritis, psoriatic arthritis);
• Patient with upper extremity pain syndrome that may interfere with the assessment of finger pain;
• Patient with another pathology responsible for neuropathic hand pain (carpal tunnel syndrome, diabetic neuropathy, Guyon's tunnel syndrome, cervicobrachial neuralgia, brachial plexitis);
• Patient with skin lesions on the fingers (psoriasis, wounds, chronic ulcers, eczema, shingles, dermatitis);
• Patient with poorly controlled high blood pressure;
• Patient with hypersensitivity to capsaicin;
• Patient who had 8% capsaicin patch use in the year prior to the study;
• Patient who has received intramuscular, intra-articular or intravenous corticosteroid therapy, another disease-modifying anti-rheumatic therapy (methotrexate, salazopyrine) or an intra-articular injection into the joints of the fingers within the previous 3 months;
• Patient wearing wrist or finger orthoses in the previous month;
• Patient with fibromyalgia;