Intra-individual variations in acute and cumulative skin irritation responses

• Published in: Contact dermatitis Vol. 45; no. 2; pp. 75 - 83
• Main Author: Robinson, Michael K.
• Format: Journal Article
• Language: English
• Published: Copenhagen Munksgaard International Publishers 01.08.2001; Blackwell
• Subjects: 1-decanol; acetic acid; Acetic Acid - adverse effects; Acute Disease; Asian Continental Ancestry Group; Biological and medical sciences; Caprylates - adverse effects; Chronic Disease; clinical; Dermatitis, Allergic Contact - diagnosis; Dermatitis, Allergic Contact - etiology; Dermatitis, Allergic Contact - pathology; European Continental Ancestry Group; Fatty Alcohols - adverse effects; General aspects. Methods; human; Humans; irritant contact dermatitis; Irritants - adverse effects; Medical sciences; octanoic acid; patch test; Patch Tests - standards; Predictive Value of Tests; response variability; Severity of Illness Index; skin irritation; sodium dodecyl sulfate; Sodium Dodecyl Sulfate - adverse effects; Toxicology; visual assessment; Human; Anionic surfactant; Intraindividual comparison; Toxicity; Chemical compound; Skin; Exposure time; Patch; Irritation; Dose activity relation; Skin test
• ISSN: 0105-1873; 1600-0536
• DOI: 10.1034/j.1600-0536.2001.045002075.x

It is well‐known that humans show a wide range of variation in skin reactivity to irritant chemicals. This has been established through population studies, through the examination of inter‐subject variability, and (to a limited extent) through studies of skin site variation in response within subjects. However, simple response variability within individual test subjects has not been examined as carefully, and this has implications for our ability to predict irritant reactivity. Some key questions are: (i) how consistently do human beings respond, even within a given study, to different equally irritating chemicals, or to the same chemical when comparing different concentrations or durations of exposure, and, (ii) Do individual test subjects’ responses to one chemical (or exposure scenario) correlate with their responses to another? To examine these questions in some detail, we reexamined individual study subjects’ responses from earlier published studies involving both acute and cumulative irritation patch test protocols. Acute irritation responses were compared across chemicals with similar irritation profiles. Cumulative irritation responses were compared across different concentrations of the anionic surfactant, sodium dodecyl sulfate (SDS). Acute (high concentration) and cumulative (low concentration) patch test responses to SDS were also compared. The analysis showed that, as might be expected, response correlations were greatest within test types, either when comparing chemicals of similar overall irritancy, or when comparing similar concentrations of a single chemical. However, individually divergent responses were also frequent, reinforcing the conclusion that a given individual’s response to one chemical or exposure condition does not always predict their response to another. This has important ramifications for other questions related to population differences in skin reactivity.