Tixocortol pivalate: what is the right concentration?

Area of Science:

• Dermatology
• Allergology
• Contact Dermatitis

Background:

• Tixocortol pivalate (TP) is a key marker for identifying hydrocortisone allergy.
• Optimal concentration of TP for standard patch testing remains debated.

Purpose of the Study:

• To determine the appropriate concentration of Tixocortol pivalate (TP) for inclusion in standard patch testing series.
• To compare the efficacy of 1% TP versus 0.1% TP in patch testing.

Main Methods:

• A multicenter study involving 3747 dermatitis patients patch tested with TP 1% and 0.1% in petrolatum.
• Data collected from August 2004 to December 2005 across 9 UK centers.
• Statistical analysis using STATISTICA version 6, including a two-tailed difference in proportions test.

Main Results:

• 41 patients exhibited positive reactions of clinical relevance.
• 20 patients were positive for both 1% and 0.1% TP concentrations.
• 13 patients reacted only to 1% TP, while 8 reacted only to 0.1% TP. No statistically significant difference was found between the two concentrations (P=0.21).

Conclusions:

• There is no statistically significant difference in reactivity between 1% and 0.1% Tixocortol pivalate concentrations in patch testing.
• Given practical limitations on the number of allergens in standard series, 1% TP is recommended for screening purposes.