New onset of remitting seronegative symmetrical synovitis with pitting oedema and palmoplantar psoriasis flare-up after Sars-Cov-2 vaccination.

Conflict of interest

Nothing to disclose.

Dear Editor,

An 83‐year‐old woman referred to the dermatology division of our hospital because of recent acute onset of stiffness with limitation in basic activities of daily living and pain, swelling and palmar skin eruption of both hands. All symptoms showed up 48 h after the second administration of BNT162b2 Pfizer/BioNTech® Sars‐Cov‐2 vaccine.

The patient presented with a history of palmoplantar psoriasis since 1996, in long‐standing remission with methotrexate (MTX) 10 mg every 10 days. She took also anti‐hypertensive and oral antidiabetic medications. She had no history of rheumatic or allergic diseases.

At physical examination, both hands on palmar side showed psoriasis with erythematous, scaly plaques, while on dorsum and wrist joints, painful oedema was present. Dactylitis was also detected in all fingers associated with severe functional impairment (Fig. 1a,b). Musculoskeletal ultrasound (MSUS) revealed tenosynovitis of the digital extensor tendon and the carpal extensor tendon of wrists based on the presence of hypoechoic signals around the tendon sheath with power Doppler signal both in transverse and in longitudinal planes (Fig. 2a,b). Acute phase reactants were elevated, rheumatoid factor was negative, and X‐rays revealed no joint erosions. The scenario indicated a flare‐up of palmar psoriasis associated with the onset of psoriatic arthritis with remitting seronegative symmetrical synovitis with pitting oedema (RS3PE). The patient started oral prednisone (25 mg once daily) and increased MTX dosage (10 mg weekly), with a rapid clinical improvement.

Figure 1

(a) Erythema and desquamation on the palm of left hand. (b) Oedema on the back of left hand and wrist joint.

Figure 2

(a) Tenosynovitis of the carpal extensor tendon. (b) Tenosynovitis of the digital extensor tendon.

New onset or exacerbation of psoriatic disease following vaccinations, though rare, is reported in literature. To date, the cases of psoriasis flare‐up have been described with influenza, pneumococcal polysaccharide, Bacillus Calmette–Guerin (BCG) and tetanus–diphtheria vaccines. , ,

In this case, the close temporal link between Sars‐Cov‐2 vaccination and the onset of psoriasis flare‐up associated with joint involvement suggests a possible causal association between the two events.

It is known that vaccination itself triggers an IFN‐gamma and TNF‐α release from Th1 cells, which could represent a possible mechanism for vaccination‐induced psoriatic disease.

Polyethylene glycol (PEG) – one of the compounds of BNT162b2 – could also have been the cause for the systemic reaction observed, acting as the antigen that activated the immune pathway as reported in other cases.

RS3Pe syndrome is characterized by symmetrical synovitis and swelling of both the upper and lower extremities. RS3PE syndrome may overlap several rheumatic disorders such as polymyalgia rheumatica, rheumatoid or psoriatic arthritis, especially at the onset in the elderly, similar to our case. The aetiology of the disease is still unknown, although some authors have related it to genetic predisposition, infectious diseases or α‐TNF released by tumours or a paraneoplastic syndrome when recovery was observed after a complete tumour removal. In literature, two cases of RS3PE following intravesical instillation of BCG , are reported.

Typical RS3PE treatment includes NSAIDs, hydroxychloroquine and corticoids, and full recovery usually occurs between 3 and 36 months after starting corticoid treatment.

To the best of our knowledge, this is the first case of palmoplantar psoriasis flare‐up and RS3PE onset after Sars‐Cov‐2 vaccination. Currently, BNT162b2 Pfizer/BioNTech ® remains a very safe and effective vaccine and its use is strongly recommended.