Substitution of renal function through skin catharsis: Evidence from the classical period to the Middle Ages

Substitution of renal function through skin catharsis: Evidence from the classical period to the Middle Ages. The skin's cleansing capacity has been known for centuries and has been used therapeutically and extensively for a great number of diseases. We studied the historical evolution of the methods used for catharsis through the skin, particularly for those in renal failure, by reviewing most of the existing ancient Greek and Byzantine codices dealing with the skin's cleansing capacity. From the fragments cited in this article, it is evident that the ancient medical writers were well aware of the mechanism of perspiration, and through this process the excretion of several body toxins, they knew about renal failure as well as the influence of environmental temperature on blood purification via the skin. To validate their views, we reviewed the seasonal variation of the average values for blood urea, creatinine, and electrolytes for 161 regular dialysis treatment (RDT) patients in four dialysis units in southern Greece. The estimations were carried out during the winter/summer 1997, 1998, and 1999 terms and included three winter months and three summer months. We traced an unexpectedly large number of references in the ancient and medieval Greek medical literature concerning detoxification through the skin, mainly regarding patients in renal failure. This seasonal variation hypothesis is supported by the results of our retrospective study: there was a difference of 16 mg/dL in the average blood urea (mean winter urea 182 mg/dL, mean summer urea 166 mg/dL). We suggest that the ancients had a vivid idea about the substitution of renal function by the skin's cleansing ability in renal failure. The previously mentioned phenomenon may be due to the elimination of blood urea through excessive perspiration. Our clinical results seem to verify their notions, and hence, the skin (like the peritoneum) may be considered a natural membrane for dialysis. We were unable to trace a similar report in the literature on the seasonal fluctuation of blood urea in dialysis patients.