Correlation between stinging, TEWL and capacitance.
OBJECTIVE
To study the correlation between stinging and skin barrier and to make the lactic acid stinging test much safer.


METHODS
The modified lactic acid stinging test with 3% and/or 5% aqueous solution of lactic acid combined with transepidermal water loss (TEWL) and capacitance (CAP) was used. The amount of 50 microL-test material was applied on test areas, the skin of both sides nasolabial fold of 50 healthy subjects. Subjects assessed stinging basing on a 4-point scale at 0, 2.5, 5.0 and 8 min TEWL and CAP were measured at baseline and 8 min.


RESULTS
The results show that the tendency of decrease in baseline CAP and increase in baseline TEWL are proportional with the increase of the sum of clinical scores (CSS). In 5% lactic acid test, negative correlation between changing ratio of TEWL (PTEWL) and clinical score at 5 min (CS5 min), and negative correlation between changing ratio of capacitance (PCAP) and CS5 min are registered.


CONCLUSIONS
Our data indicate that there is certain relationship between the degree of stinging and the skin barrier. The stinging test method modified by lower concentration aqueous lactic acid and the assessment combined with PTEWL and PCAP is suitable for Chinese to evaluate the skin susceptibility.
Wu
Yanyu
Y
College of Medicine, Tong Ji University, Shanghai 200065, PRC.
Wang
Xuemin
X
Zhou
Yutian
Y
Tan
Yimei
Y
Chen
Deli
D
Chen
Ying
Y
Ye
Meili
M
D000287:Administration, Topical; D000328:Adult; D001834:Body Water; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D004305:Dose-Response Relationship, Drug; D025802:Electric Capacitance; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009666:Nose; D010147:Pain Measurement / Q000379:methods*; D017288:Pain Threshold; D012882:Skin Tests / Q000379:methods*; D013223:Statistics as Topic; D014110:Touch; D014870:Water Loss, Insensible
D019344:Lactic Acid