Comparative Measurement of Skin Surface Hydration Using a Hydrometer and Corneometer

Lee, Seung Hun; Chung, Joon; Ahn, Sung Ku; Kang, Jin Soo; Kwon, Oh Kyu

Abstract

BACKGROUND: Hydration, the water content of the stratum corneum, is an important factor in both the appearance and the barrier function of the skin. Many non-invasive methods have been developed in order to assesa the hydration state of the skin and the effect of various moisturizers. The hydrometer and carneometer are commercially available instruments which are widely used in dermatologic research.
OBJECTIVE
Our purpose was to compare the measuring usefulnes of both instruments on normal subjects with a wide range of hydration states of the hornylayer.
METHODS
We measured the conductance with the hydrometer and the capacitance with the corneometer in various hydrating eonditions and compared both insruments.
RESULTS
Conductance had a non linear correlation with capacita ice. Capacitance measured with the corneometer had a high sensitivity to moisture in a wide range of hydration levels. On the other hand, conductance guaged with the hydrometer showed a few sensitivity to moisture at a low level. When the hydretion level was measured after a moiturizer was added, 10 % urea cream showed a sharp increase by 256% in terms of conductanae, and H-base by 97.8%. Mineral oil decreased by 41.5% and petrolatum by 62% respectively. On the other hand, when measured in terms of capacitance under the same conditions as above, 38.9 increase in 10% urea cream, 19.3% increase in H-base, 20% decrease in mineral oil, and 43.5 % decrease in petrolatum were reported. Conductance showed a higher hygroscopicity and a lower water holding capacity than capacitance did. When the measurement of the moisture level iri virious parts of the human body is performed, the corneometer provided us with more stable alies than the hydrometer. While the hydrometer can not the available and appropriate under the condition of insulation, the corneometer can measure moisture levels even down at the depth of 250mm. When measured after the oily surface of the forehead was cleansed with soft tissue, conductance and capacitance revealed higher values of moisture levels than before the eleanin. However, there is no statistical significance in these values.
CONCLUSION
The hydrometer is a more appropriate tool for the measurement of moisture at a high level, and the corneometer at a low moisture level. The hydrcmeter is a more sensitive method of measuring the increase and the decrease in the moisture level.