A stronger patch test elicitation reaction to the allergen hydroxycitronellal plus the irritant sodium lauryl sulfate

Household and cleaning products often contain both allergens and irritants. The aim of this double-blinded, randomized, paired study was to determine whether patch testing with an allergen (hydroxycitronellal) combined with an irritant [sodium lauryl sulfate (SLS)] cause a stronger patch test elicitation reaction than patch testing with the allergen (hydroxycitronellal) alone, in patients previously patch tested positive to hydroxycitronellal. A stronger patch test elicitation reaction was defined as at least 1 day of patch test reading showing more positive patch tests (+, ++ or +++) on the forearm patch tested with 6 concentrations of SLS plus hydroxycitronellal than on the forearm tested with 6 concentrations of hydroxycitronellal alone and no day of patch test readings showing more positive tests on the hydroxycitronellal forearm. 15/20 (75%) had at least 1 day of patch test reading with more positive patch tests on the forearm patch tested with SLS plus hydroxycitronellal and no day of patch test readings with more positive patch tests on the forearm tested with hydroxycitronellal (P = 0.0253). Estimation of the blood flow with laser Doppler supported these findings.

Use of the local lymph node assay in the evaluation of the sensitizing potential of pharmaceutical process intermediates

The murine local lymph node assay (LLNA) has recently been developed to determine the contact sensitization potential of chemicals. Since its original development, the LLNA results have been the subject of extensive comparisons with guinea pig and human data. The investigations described here were designed to explore the ability of the LLNA to identify accurately, pharmaceutical process intermediates (PIs) known to cause contact allergy in humans. To that end, 16 PIs previously tested in the guinea-pig maximization test (GPMT) were tested in the LLNA. Another PI known to be a contact sensitizer in humans was tested only in the LLNA. Cases of contact sensitization in humans were reported only for PIs that were extreme sensitizers in the GPMT and had low EC3 values (concentration of the test substance required to generate a threefold increase in lymph node cell proliferation) in the LLNA. These data provide additional evidence that the LLNA is able to discriminate skin sensitizers from chemicals that do not possess a significant skin sensitization potential and is thus a useful method for hazard identification. In addition, this method also offers important animal welfare benefits and may also be useful for risk assessment purposes.

Systemic acyclovir reaction subsequent to acyclovir contact allergy: which systemic antiviral drug should then be used?

Allergic contact dermatitis caused by acyclovir is rare. We report the 5th case of systemic acyclovir reaction subsequent to acyclovir contact dermatitis, with investigations made to determine an alternative antiviral treatment. A 23-year-old woman, after dermatitis while using Zovirax cream, went on to develop urticaria after oral acyclovir. Patch tests were performed with the components of Zovirax cream (acyclovir, propylene glycol and sodium lauryl sulfate) and with other antiviral drugs. Patch tests were positive to Zovirax cream, acyclovir, valacyclovir and propylene glycol. Patch and prick tests with famciclovir were negative, but its oral administration caused an itchy erythematous dermatitis on the trunk and extremities. Our patient developed a systemic acyclovir reaction subsequent to acyclovir allergic contact dermatitis, with cross-reactions to valacyclovir and famciclovir. Their common chemical structure is the 2-aminopurine nucleus. It is probably this part of the molecule that provokes both contact allergy and systemic reactions. The only antiviral drugs not having this core are foscarnet and cidofovir, and these could therefore be alternatives.

Nonanoic acid - an experimental irritant

Irritant contact dermatitis is defined as a non-immunological skin reaction following exposure to various chemical, mechanical and physical factors. It is known that the skin response to irritants depends on the irritant applied and differs between chemically different irritants. Sodium lauryl sulfate (SLS) is an anionic detergent and the most frequently used substance in experimental irritant contact dermatitis. In 1980, it was suggested that nonanoic acid (NNA) could be used as a positive control when patch testing. Since then, NNA has been used as an experimental irritant in several studies and has been used as a chemically different substance compared to SLS. The present article presents a review of the application of NNA in studies on skin irritancy and experimental irritant contact dermatitis.

The association between ambient air conditions (temperature and absolute humidity), irritant sodium lauryl sulfate patch test reactions and patch test reactivity to standard allergens

To support the decision as to whether erythematous patch test reactions to allergens are irritant or allergic, sodium lauryl sulfate (SLS, 0.5% in water) has been added to the standard patch tests since July 1996 in the Dortmund Department of Dermatology. Data on 1600 patients patch tested up until June 2001, as well as standardized data on ambient temperature and humidity obtained by the German Meteorological Service, were included in a logistic regression analysis taking age, sex and atopy as potential confounders into account. The pattern of association was heterogeneous: while doubtful reactions to nickel sulfate were significantly associated with dry/cold weather conditions, but not with SLS reactivity, the opposite was observed for lanolin alcohol, benzocaine and Myroxylon pereirae resin (balsam of Peru). Doubtful reactions to other allergens, namely formaldehyde, fragrance mix or p-phenylenediamine, were associated with both factors. For several other allergens of the standard series, no distinct, significant pattern could be discerned. In conclusion, meteorological conditions and SLS reactivity independently contribute information on individual irritability at the time of patch testing, and both should be considered.

Evaluation of the histologic characteristics of patch test confirmed allergic contact dermatitis

BACKGROUND

Microscopic features of experimentally induced allergic contact dermatitis (ACD) have been reported; however, the histologic characteristics of environmentally induced ACD have not been definitively elucidated.

OBJECTIVE

This pilot study was conducted to describe the histologic features most useful in differentiating ACD from other forms of eczematous dermatitis.

METHODS

A retrospective chart review of patients who underwent evaluation for contact dermatitis was performed. The results of skin biopsy were reviewed in a blinded manner, and two subgroups were compared: gold standard ACD cases and control cases (eczematous dermatitis with negative results of patch testing).

RESULTS

Of 317 cases reviewed, 39 fulfilled the inclusion criteria. Many histologic similarities were noted: both subgroups had substantial acanthosis and lymphocytic infiltration. In addition, present to a moderate degree in both groups were hyperkeratosis, spongiosis, eosinophils, and dermal dendritic fibrohistiocytic (DFH) cells. However, compared with the control cases, eosinophilic spongiosis and multinucleate dermal DFH cells were found to a considerably greater degree in the standard ACD cases.

CONCLUSIONS

Eosinophilic spongiosis and multinucleate dermal DFH cells, in the presence of acanthosis, lymphocytic infiltrate, dermal eosinophils, and hyperkeratosis, are particularly suggestive of ACD. While such findings alone are not diagnostic of ACD, the presence of these combined histologic features supports the pursuit of patch testing in cases of chronic eczematous dermatitis.

The detection of clinically relevant contact allergens using a standard screening tray of twenty-three allergens

BACKGROUND

The current standard tool for diagnosing allergic contact dermatitis (ACD) in the United States is the T.R.U.E. test panels, which consist of 23 allergens. Previous studies have raised concern regarding the adequacy of these panels in fully assessing patients with possible ACD.

OBJECTIVE

We sought to examine the use of the T.R.U.E. test allergens as the primary diagnostic method for detecting ACD.

METHODS

A retrospective analysis of all patients with possible ACD who presented to the University of Kansas' Section on Occupational and Contact Dermatitis in Kansas City, Kansas, and subsequently underwent patch testing from January 1, 1995, to December 31, 2001. Patients with positive allergic reactions were stratified into 3 groups: (1) reactions only to allergens on the T.R.U.E. test; (2) reactions only to allergens not present on the T.R.U.E. test; and (3) reactions to allergens on the T.R.U.E. test and additional allergens. These 3 groups were further analyzed to assess clinical relevance.

RESULTS

Of the 898 patients who were patch tested, 616 (68.6%) had at least 1 positive allergic reaction. Among these 616 patients, 25.5% would have been fully evaluated using the T.R.U.E. test allergens only. Of the remaining patients, 22.4% would not have had any of their allergens detected and 52.1% would have only been partially evaluated had only the T.R.U.E. test allergens been used. Similar percentages were observed when only patients with clinically relevant reactions were included.

CONCLUSIONS

In our study, the current T.R.U.E. test series of 23 allergens would have completely identified all allergens in only 25.5% of patients and clinically relevant allergens in 28% of patients. Expanding the number of allergens used according to a patient's environment and history will lead to improved outcome in the treatment and prevention of ACD.

ELISpot: a new tool for the detection of nickel sensitization

BACKGROUND

The standard assay for the clinical detection of contact allergy against nickel is the patch test. For research purposes, the in vitro lymphocyte transformation test (LTT) is mostly applied. However, the in vivo application of allergens includes the potential of sensitization, whereas the LTT demands 6 days of cell culture and radioactive labelling procedures.

OBJECTIVE

The purpose of this study was to validate an enzyme-linked immunospot (ELISpot) assay to specifically detect cellular response against nickel sulphate in correlation with patch test, anamnestic data, and LTT results.

METHODS

In probands with positive (n=60) and negative patch test results (n=19), cytokine ELISpot and LTT were performed in parallel using various concentrations of nickel sulphate, various numbers of responding peripheral blood mononuclear cells (PBMC), and various durations of cell cultures.

RESULTS

Concentrations of 50 and 75 microM nickel sulphate were found to be optimal to stimulate in the ELISpot 4x10(5) and in the LTT 2x10(5) PBMC, respectively. An increase in ELISpot sensitivity was reached by pre-incubation with nickel sulphate for 24 h prior to transfer to ELISpot plates. In nickel-sensitive probands, an average precursor cell frequency of 19x10(5), 1.7x10(5), and 0.7x10(5) could be defined for IFN-gamma, IL-2, and IL-4 producing PBMC, respectively. In non-sensitive probands IFN-gamma producing cells were detectable, but with significantly lower frequency (2x10(5); P=0.004). The prior performance of patch tests had no significant effect on cytokine production or lymphocyte proliferation. Overall, the parameters patch test, anamnestic nickel allergy, ELISpot, and LTT results were positively correlated (P<0.05).

CONCLUSIONS

Based on these experiments, the quantitative in vitro detection of cell-mediated reactions towards nickel as well as other heavy metal ions should be possible utilizing the above-described ELISpot assay.

[Decrease in nickel sensitization in young patients--successful intervention through nickel exposure regulation? Results of IVDK, 1992-2001]

BACKGROUND

In the early 1990s, the prevalence of nickel contact allergy was high-almost 20% on a population level, and some 40% in contact dermatitis patients. Around that time, nickel exposure was starting to be regulated.

PATIENTS/METHODS

Descriptive and bivariate analyses of patch test results of all patients tested with nickel sulfate (5% pet.) in the departments joining the Network of Departments of Dermatology (IVDK) 1992-2001 (n=82,991, women: 52,709; men: 30,282). The annual frequency of sensitization to nickel was analyzed in women and men in four age subgroups (<31/31 to <44/44 to 58= or >58).

RESULTS

In young women less than 31 (n=13.909) the prevalence of contact allergy to nickel decreased significantly from 36.7% in 1992 to 25.8% in 2001. In young men in the same age group (n=7087), the prevalence dropped from 8.9% in 1992 to 5.2% in 2001.

CONCLUSIONS

The observed decline indicates that measures to limit the release of nickel from costume jewelry helped reduce the prevalence of nickel allergy. In general term, allergen elimination or reduction is an effective primary prevention strategy which does not depend on individual behavior modifications.