Fruit acids and sodium hydroxide in the food industry and their combined effect with sodium lauryl sulphate: controlled in vivo tandem irritation study.
BACKGROUND
Cutaneous exposure to a variety of irritants has been extensively studied in recent years. Nevertheless, knowledge of the induction of irritant dermatitis, especially by mild irritants at low doses and for a short duration of exposure, is still incomplete.


OBJECTIVE
To quantify the irritant effects and barrier disruption properties of ascorbic acid (ASC), acetic acid (ACA) and sodium hydroxide (NaOH), particularly in combination with an anionic detergent, sodium lauryl sulphate (SLS).


METHODS
In a tandem repeated irritation test, the irritants were applied for 30 min twice daily for 4 days to the skin of the mid-back of 19 healthy volunteers of both sexes. We used bioengineering techniques for measurement of transepidermal water loss (TEWL) and skin colour reflectance, as well as visual scoring.


RESULTS
Repeated application of ASC and ACA caused a moderate increase in TEWL and erythema. The sequential application of ASC or ACA and SLS enhanced these effects. NaOH induced a strong reaction when applied both occlusively and nonocclusively as well as in combination with SLS, with an early onset of the inflammatory signs, leading to discontinuation of the application on the third day in most of the test fields. Notably, the irritant effect of NaOH was not as marked when applied sequentially with SLS.


CONCLUSIONS
Our results demonstrate that concurrent application of an anionic detergent and a mild acidic irritant can lead to disruption of the barrier function which, although not additive, is still considerable. The combined application of SLS and mild acids does not prevent SLS-induced irritation. Furthermore, we showed that NaOH in low concentrations may also act as a potent irritant but that its effect is not enhanced by SLS. The necessity of adequate skin protection and reduction of contact with substances that are potentially barrier disruptive and irritant, e.g. in the food industry, is emphasized, not only when handling detergents, but also when processing food products.
Fluhr
J W
JW
Skin Physiology Laboratory, Department of Dermatology, Friedrich-Schiller-University, Erfurter Str. 35, 07740 Jena, Germany. joachim.fluhr@derma.uni-jena.de
Bankova
L
L
Fuchs
S
S
Kelterer
D
D
Schliemann-Willers
S
S
Norgauer
J
J
Kleesz
P
P
Grieshaber
R
R
Elsner
P
P
D019342:Acetic Acid / Q000633:toxicity*; D000328:Adult; D001205:Ascorbic Acid / Q000633:toxicity*; D017453:Dermatitis, Irritant / Q000209:etiology* / Q000503:physiopathology; D004347:Drug Interactions; D004890:Erythema / Q000139:chemically induced; D005260:Female; D005525:Food-Processing Industry; D005638:Fruit / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced; D010328:Patch Tests / Q000379:methods; D016037:Single-Blind Method; D012967:Sodium Dodecyl Sulfate / Q000633:toxicity; D012972:Sodium Hydroxide / Q000633:toxicity*; D013501:Surface-Active Agents / Q000633:toxicity; D014870:Water Loss, Insensible / Q000187:drug effects
D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D012972:Sodium Hydroxide; D001205:Ascorbic Acid; D019342:Acetic Acid