Clinical Aspects of Irritant Contact Dermatitis

Irritant Contact Dermatitis — a Review

Purpose of Review

Recent Findings

Summary

Differentiating allergic and irritant contact dermatitis by high-definition optical coherence tomography: a pilot study

Differentiation of allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD) is important because of different management requirements. Various non-invasive tests have been used in an attempt to improve diagnosis. In irritant dermatitis, thickening of the epidermis has been a constant finding. High-Definition Optical Coherence Tomography (HD-OCT) is a non-invasive real-time three-dimensional imaging technique with cellular resolution for which an adapted algorithmic method for pattern analysis discriminating inflammatory skin diseases has been proposed. The aim of this study was threefold. (1) To evaluate the correlation between HD-OCT features and clinical scores of allergic and irritant patch test reactions. (2) To explore the potential of HD-OCT in optimizing the visual patch test scoring. (3) To assess in vivo the cytological and 3-D micro-architectural differences in skin reaction types between doubtful positive ACD and ICD. Twenty-two volunteers were patch tested using potassium(VI)dichromate, cobalt(II)chloride, nickel(II) sulfate and palladium(II)chloride. Visual patch test scoring and HD-OCT assisted patch test scoring were performed at 48 and 96 h after patch test application according to ECDRG guidelines. Selected HD-OCT features correlated well with clinical severity scores. HD-OCT assessment improved the visual patch test scoring although not significantly. Increased epidermal thickness observed in ICD at first reading was a significant finding useful in differentiating doubtful (+?) ACD from irritant (IR) ICD reactions. In conclusion, HD-OCT might be a unique tool for in vivo non-invasive real-time three-dimensional epidermal thickness measurements helping to differentiate IR from doubtful (+?) reactions in patch testing. Selected HD-OCT features corresponded well with severity of visual scoring. These features might help to quantify the degree of inflammation in inflammatory skin conditions. HD-OCT might help in optimizing visual patch test scoring in some situations.

Cytokine gene polymorphisms and susceptibility to chronic irritant contact dermatitis

BACKGROUND

Cytokines play an important role in skin inflammation.

OBJECTIVES

We determined whether polymorphisms in cytokine genes contribute to the occurrence of occupational chronic irritant contact dermatitis (CICD).

METHODS

In a case-control study, 9 polymorphisms in the genes coding for interleukin (IL)-1 alpha, IL-1 beta, IL-8, IL-10, and tumour necrosis factor (TNF)-alpha were determined in 197 patients with CICD. 217 apprentices in vocational training for high-risk occupations for CICD served as controls.

RESULTS

For all polymorphisms, no differences in genotype distributions were found between patients and controls. However, in patients with self-reported low levels of wet work and irritant exposure, more TNFA -308 variant genotypes (G/A and A/A) were present compared with those exposed to higher levels or controls, which indicates a TNFA-induced increase of susceptibility. In patients with TNFA -308 variant genotypes, the prevalence of flexural eczema was higher (48% and 57%) compared with that in patients presented with wild-type genotype (30%). Regarding IL1A -889, prevalence of symptoms of dermatitis was lower in apprentices with T/T or C/T genotype (32% and 36%) compared with wild-type genotype (54%, C/C). This indicates a protective effect of these variant alleles in acquiring hand dermatitis.

CONCLUSIONS

This study provides evidence that some genetic variations alter susceptibility to (chronic) dermatitis. Knowledge of the impact of genetic differences on the risk of CICD is essential in predictive testing of individuals at risk.

Site variations in susceptibility to SLS

According to the European Society of Contact Dermatitis (ESCD) guidelines on the sodium lauryl sulfate (SLS) exposure test 'the flexor side of forearm skin with cubital fossa and wrist excluded is the preferred study site'. In this study we analysed the exact anatomic region within the suggested test area in respect to the outcome of the SLS exposure test. 3 test areas at the volar forearm were chosen: 'distal' with a 5-cm distance to the wrist, exact 'midvolar' and 'proximal' with a 5-cm distance to the cubital fossa. 25 healthy volunteers were irritated for 24 hr with 1% SLS. Transepidermal water loss (TEWL) measurements were taken before and 1 and 24 hr after removal of Finn Chambers((R)). Median baseline TEWL showed no significant differences in the 3 test sites. However, postexposure TEWL proximal was significantly (P < 0.01) higher than midvolar and distal. The distal volar forearm showed the lowest TEWL 24 h after the irritation. The differences were in comparison to midvolar (P < 0.01) and proximal (P < 0.001) significant. The results show that it is essential to point out the exact position of the test area at the volar forearm in study reports and to randomize the irritation areas at the volar forearm if different treatments are to be compared.