[Thermography of collagen diseases with Raynaud's phenomenon]

In forty-four patients with collagen diseases accompanied with Raynaud's phenomenon(systemic lupus erythematosus(SLE)10, progressive systemic sclerosis(PSS)15, primary Sjögren's syndrome(PSJS)18 and mixed connective tissue disease(MCTD)1), we analyzed the thermography of fingers after thermal stimulation with cold water(15 degrees C, 30 seconds). In normal controls, the temperature of the distal points of fingers was higher and recovered more quickly than that of the proximal points(proximal interphalangeal joint; PIP). But in the patients with Raynaud's phenomenon, the temperature of distal point of fingers was lower and recovered more slowly than that of proximal points. Because the difference of the temperature between the distal and the proximal points (DP)is a good parameter to distinguish these two thermographic patterns, we analysed DP. DP is less influenced by room temperature than the temperature of fingers and the recovery temperature after thermal stimulation which have been used as indicators of Raynaud's phenomenon. DP in the normal controls was significantly higher than that in the patients. DP in PSS was lower than that in SLE and PSJS, and statistically associated with the markers of disease activities, such as erythrocyte sedimentation rate, titers of anti-RNP antibody and diffusing capacity of lung. These results show that thermographic pattern and the value of DP are the useful indicator of severity of Raynaud's phenomenon.