A patient with Sjögren's syndrome and seronegative polyarthritis is reported. After piroxicam intake and sun exposure she developed subacute cutaneous lupus erythematosus lesions with Ro antibodies. Despite drug withdrawal, typical cutaneous lesions and serological markers of systemic lupus erythematosus (SLE) progressively appeared. The use of piroxicam and other nonsteroidal anti-inflammatory drugs with photosensitizing potential in patients with Sjögren's syndrome, sicca syndrome or a high suspicion of a collagen disorder should be avoided because these drugs may trigger a latent SLE.