Does Salt and Mineral Content of Dead Sea Mud Affect Its Irritation Potential: A Laser Doppler Flowmetry Study

The aim of the study was to investigate skin microcirculation, flux, and temperature changes induced by the application of Dead Sea mud (DSM) formulas with different mud salts and mineral contents using laser Doppler flowmetry. Instrumental analysis of eight over-the-shelf DSM products and four different samples of nonformulated Dead Sea mud were carried out to determine their contents of various salts and elements, including K, Na, Cl, Mg, Mn, Ca, SO₃, SiO₂, Al, Br, Fe, Hg, Cr, Co, Ni, Cu, Zn, As, Cd, Pb, and Sr. Three DSM samples with different levels of salts were then used to study the influence of salt content on skin irritation potential using laser Doppler flowmetry. Fifteen healthy nonsmoking females aged 18-45 years participated in the study. Subjects were randomly assigned to either "Salted" mud group (n = 5), "As is" mud group (n = 5), or "Over-the-Shelf" mud group (n = 5). Five circular areas were marked on the ventral aspect of each forearm. One forearm was assigned randomly for mud treatment and the other forearm was untreated. Ten milliliters of mud was applied on the assigned forearm and left for 30 minutes. Two reading protocols were designed and used to study the effects of tested type of mud on skin blood flux and temperature during mud application (protocol 2) as well as before and after mud removal (protocol 1). All types of tested mud were not associated with a significant measurable elevation in skin temperature and skin blood flow. All types of Dead Sea mud did not cause detectable microcirculatory and skin temperature changes regardless of their different mineral and salts contents.