Ai-Lean Chew

Physical and physiological effects of stratum corneum tape stripping

Background/aims: Tape stripping of human stratum corneum has been performed to measure stratum corneum mass, barrier function, drug reservoir and percutaneous penetration. However, the technique itself requires further development to facilitate interpretation.

Efficacy of corticosteroids in acute experimental irritant contact dermatitis

Background/aims: Topical corticoids are used to treat irritant contact dermatitis (ICD) in humans. However, their clinical efficacy remains sub judice. This study was designed to assess the efficacy of low‐ and medium‐potency corticosteroids on irritant dermatitis.

Provocative use test of nickel coins in nickel‐sensitized subjects and controls

Summary  Background Consensus exists on levels of nickel release that are well tolerated in exposure to nickel‐containing items in direct and continuous contact with skin (e.g. watches). The clinical relevance of nickel‐containing coins eliciting nickel dermatitis associated with extensive occupational exposure (e.g. coins handled by cashiers) has not been determined.

1,2-benzisothiazolin-3-one (Proxel®) : irritant or allergen : A clinical study and literature review

The isothiazolinone, 1,2‐benzisothiazolin‐3‐one (Proxel®), is a popular preservative, as well as a skin sensitizer and irritant. Patch test studies have been performed with different concentrations and vehicles. The current suggested patch test concentration is 0.1% BIT in petrolatum (pet). This article evaluates the effects of patch testing at this concentration and reviews the current literature. An irritancy patch test was performed on 56 controls, using BIT in concentrations of 0.002% and 0.05% in aqueous dipropylene glycol (Proxel® GXL) and 0.1% in pet. 10 had positive readings at 4 days with 0.1% BIT in petrolatum. 9 of which were negative at retest. 0.1% BIT is, therefore, irritant and not a suitable concentration for patch testing. Literature review revealed 15 patch test studies, with varying testing techniques. Additional studies with adequate controls and experimental tests should be invaluable in furthering our insight into BIT sensitization and irritation.

In Vitro Methods to Predict Skin Irritation

Whole-animal tests represent true physiological and metabolic relationships of macromolecules, cells, tissues, and organs that can evaluate the reversibility of toxic effects. However, these tests are costly, timeconsuming, insensitive, and difficult to standardize and are sometimes poorly predictive of human in vivo response.