PRIMARY RAYNAUDS-PHENOMENON - AGE-OF-ONSET AND PATHOGENESIS IN A PROSPECTIVE-STUDY OF 424 PATIENTS

Many authors consider that late onset is a suspect criterion for diffe rentiating primary Raynaud's phenomenon (Raynaud's disease, RD) from R aynaud's syndrome (RS). However, many cases of late-onset Raynaud's ph enomenon in patients over forty years of age remain without etiologic diagnosis and therefore deserve the designation ''late-onset RD.'' One hundred and ninety-four patients with RD (143 women, 51 men) were sel ected among 424 patients with Raynaud's phenomenon, according to Allen and Brown's criteria with negative serologic investigations and norma l capillaroscopy. The purpose of the study was to consider the possibl e discriminant value of age of onset in distinguishing between RD and RS. The following epidemiologic features were studied: age of onset, s ex, family history of Raynaud's phenomenon and migraine, and smoking a nd working habits. Microcirculation was assessed by capillaroscopy and strain-gauge plethysmography. Maximal digital flow at 45-degrees-C an d reactivity to cold were determined for each patient. Results were re lated to age of onset. The existence of true cases of late-onset RD in patients over forty years of age was confirmed (prevalence 27%), show ing a correlation with a family history of Raynaud's phenomenon inferi or to that found in early-onset cases (p < 0.0001). Microcirculation s tudies generally indicated a strong correlation between reactivity to cold, familial RD, and early onset, whereas no correlation was found w ith migraine or smoking. Nor was there any clinical or plethysmographi c evidence for arteritis as a possible pathogenetic factor in late-ons et RD. These results indicate that late-onset RD is a valid designatio n and that its pathogenesis seems less dependent on genetic sensitivit y to cold than that of early-onset cases. In the absence of underlying arteritis, neurovascular dysfunction or a hemorheologic mechanism may be suggested as plausible causes of late-onset RD.