The development and course of test reactions to gold sodium thiosulfate

The benefit of late readings in patch testing depends both on allergen and patient characteristics

BACKGROUND

Patch test (PT) readings are recommended after 48 h and 72 h (D3). An additional day 7 (D7) reading has been suggested by some, although data on efficient patient selection are scarce. We investigated positive D7 reactions regarding (i) allergens in the baseline series and additional PT series of the German Contact Dermatitis Research Group (DKG) and (ii) characteristics of the patients tested.

METHODS

Retrospective, multicentre analysis of 190 allergens derived from 17 DKG test series in 4687 patients with an additional D7 reading. Patients were patch tested with the baseline series and additional series, if required. Occurrence of novel D7 reactions as well as increasing skin reactions from D3 to D7 was analysed separately.

RESULTS

Depending on the allergen tested, waiving D7 readings would have missed 4.4-26.8% of positive PT results. Patch test series with the highest number of novel D7 reactions were baseline series, metal series, and leather/shoe series. New positive reactions on D7 were associated with age over 50 years and with a negative irritant control containing sodium lauryl sulphate. Of note, application of the PT allergens for 48 h instead of 24 h was positively associated with late PT reactions.

CONCLUSION

Within the most frequently tested allergens, without late readings, on average 11.7% of sensitizations would have been missed. Novel late reacting allergens were identified. This study comprehensively dissects patient-, allergen- and test-dependent parameters in support for D7 readings. We propose to always consider late readings individually based on effort-benefit considerations.

Persistent Reaction to Bacitracin after Patch Testing with Thin Layer Rapid Use Epicutaneous Test

Long-lasting allergic patch test reactions (LLAPTR) are reactions that remain positive for two weeks or more after the application of the allergen. LLAPTR of longer than 6 weeks duration is rarely seen. Here we present a 54-year-old female patient who had a positive allergic reaction to bacitracin with the thin layer rapid use epicutaneous test (TRUE test), which lasted for about 11 weeks duration. To our knowledge this is the first reported case of LLAPTR related to the bacitracin.

Multicenter 1-month follow-up study of the patch-test reaction to the gold sodium thiosulfate of the TRUE Test and its association with piercings and dental metal history

BACKGROUND

There is controversy over late and long-lasting reactions to gold sodium thiosulfate (GST).

OBJECTIVES

To study the GST patch-test reaction by observing the application site after 1 month, and to clarify the relevance of GST sensitization by piercings and dental metals.

PATIENTS

A retrospective analysis was performed on 746 patients (143 male; 603 female) who were patch tested using GST of the TRUE Test. We conducted a questionnaire on the presence of piercings or dental metals in these patients.

RESULTS

The GST positive rate was 27.9% at day (D)3 and/or D7 and 40.3% up to the 1-month reading. The positive rate was significantly higher in female patients and increased with age. Sixty-two percent of cases with a positive reaction at D7 continued to show a positive reaction after 1 month. Eleven percent of cases with a negative reaction at D3 and D7 showed a late reaction. Both piercings and dental metals were related to gold sensitization.

CONCLUSIONS

The GST of the TRUE Test had a high positive and low false-negative rate. The 1-month reading after the patch test was important for identifying late reactions. Piercing history and dental metal were associated with gold sensitization.

Allergic reactions to lower concentrations of nickel sulfate and formaldehyde often appear later than reactions to higher concentrations

BACKGROUND

A late-appearing patch test reaction may be a sign of active sensitization or represent a delayed elicitation reaction.

OBJECTIVES

To retrospectively study the effect of concentration on the time course of allergic reactions to routine concentration dilution series of formaldehyde and nickel sulfate.

METHODS

We tested concentration dilution series of 2%, 1%, 0.32% and 0.1% formaldehyde and 5%, 1.6%, 0.5% and 0.16% nickel sulfate, respectively. The last readings were performed on day 4 to day 6. We included patients with allergic reactions to either of the two lowest concentrations in each dilution series and whose tests had been read three times.

RESULTS

Forty-two nickel-allergic and 23 formaldehyde-allergic patients fulfilled the inclusion criteria. In 26 (62%) of the nickel-sensitive patients, reactions to lower concentrations appeared later than reactions to the highest concentration. Of the formaldehyde-sensitive patients, 17 (74%) developed one or two allergic reactions to lower concentrations later than reactions to the highest concentration, and one (4%) patient developed allergic reactions to lower concentrations sooner than a reaction to the highest concentration. The remaining patients showed all allergic reactions at the same reading.

CONCLUSIONS

In these selected, relatively strongly sensitized patients, allergic reactions to lower concentrations quite regularly appeared later than reactions to higher concentrations.

Positive reactions to gold sodium thiosulfate in patch test panels (TRUE Test) in Japan: A multicentre study

Background

The proportion of positive test results with gold sodium thiosulfate included in a patch test panel (P‐GST) had been found to be greater than that with gold sodium thiosulfate 0.5% pet. by allergEAZE (A‐GST).

Objectives

To compare positive reactions to P‐GST and A‐GST, and to evaluate late reactions after the day (D) 7 reading.

Methods

A retrospective analysis was performed of 588 patients at participating departments (119 males; 469 females) who were patch tested with P‐GST and A‐GST in May 2015 to March 2016.

Results

Positive test reactions to P‐GST and A‐GST were observed in 15% and 6% of patients, respectively. Three patients reported a positive reaction occurring after the D7 reading.

Conclusions

Gold sodium thiosulfate often gives a positive reaction after 2 to 3 weeks, and, in such cases, the positive reaction may be sustained, so it is recommended to assess the reaction for up to 1 month after application.

Can the epoxides of cinnamyl alcohol and cinnamal show new cases of contact allergy?

BACKGROUND

Cinnamyl alcohol is considered to be a prohapten and prehapten with cinnamal as the main metabolite. However, many individuals who are allergic to cinnamyl alcohol do not react to cinnamal. Sensitizing epoxides of cinnamyl alcohol and cinnamal have been identified as metabolites and autoxidation products of cinnamyl alcohol.

OBJECTIVE

To investigate the clinical relevance of contact allergy to epoxycinnamyl alcohol and epoxycinnamal.

METHODS

Irritative effects of the epoxides were investigated in 12 dermatitis patients. Epoxycinnamyl alcohol and epoxycinnamal were patch tested in 393 and 390 consecutive patients, respectively. In parallel, cinnamyl alcohol and cinnamal were patch tested in 607 and 616 patients, respectively.

RESULTS

Both epoxides were irritants, but no more positive reactions were detected than when testing was performed with cinnamyl alcohol and cinnamal. Late allergic reactions to epoxycinnamyl alcohol were observed. In general, patients with late reactions showed doubtful or positive reactions to cinnamal and fragrance mix I at regular patch testing.

CONCLUSION

The investigated epoxides are not important haptens in contact allergy to cinnamon fragrance. The high frequency of fragrance allergy among patients included in the irritancy study showed the difficulty of suspecting fragrance allergy on the basis of history; patch testing broadly with fragrance compounds is therefore important.

How to optimize patch testing with diphenylmethane diisocyanate

We have previously shown that patch test preparations of polymeric diphenylmethane diisocyanate (PMDI) are more stable than preparations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI). This study was conducted to (i) investigate whether PMDIs yield as many positive reactions as 4,4'-MDI, (ii) study concurrent reactions to 4,4'-MDI and 4,4'-diaminodiphenylmethane (4,4'-MDA), and (iii) follow the course of positive reactions during 4 weeks. It was shown that PMDIs detect as many positive reactions as 4,4'-MDI. Thus, they are better patch test agents being more stable than preparations of 4,4'-MDI. We recommend that PMDIs with a monomer content of at least 35% is used in 2.0% petrolatum (pet.) (i.e. monomer patch test concentration approximately 0.7%). It was shown that reactions to 4,4'-MDI and PMDIs appear late and we recommend readings on both day (D) 3/4 and D7. 4,4'-MDA was shown to be a good marker for 4,4'-MDI and patch testing with 4,4'-MDA in 0.25% pet. can be used instead of PMDI. Concomitant reactions to 4,4'-MDI and 4,4'-MDA are probably not caused by conversion of 4,4'-MDI into 4,4'-MDA by reaction with water. Another explanation is a path of reactions leading to ureas and MDI conjugates with skin constituents, which are hydrolysed into 4,4'-MDA. This complex process depends upon several factors and might explain why positive MDI reactions appear after D7.

Long-lasting patch reactions to gold sodium thiosulfate occurs frequently in healthy volunteers

In a skin irritancy study in healthy volunteers with 3 metal salts, aqueous gold sodium thiosulfate (GSTS) in a dilution series caused unexpectedly frequent and strong patch test reactions on volar forearm skin in 22 of 31 participants (71%). The reactions showed morphological features consistent with a contact allergic reaction, and the crescendo type of the response speaks in favour of an allergic nature. Further, 8 of the 31 (26%) developed long-lasting test reactions. A follow-up interview among 28/31 participants 10 years later showed that none had experienced long-term consequences in the form of skin and/or mucosal complaints related to exposure to gold items. The results indicate that inclusion of GSTS in routine patch testing may cause problems regarding interpretation and clinical relevance of positive GSTS patch tests, which fulfil the clinical criteria of a contact allergy.

Late reactions in patch tests: a 4-year review from a clinic of occupational dermatology

Late patch test reactions on day (D) 10-14, which on subsequent retesting appear in the normal time schedule on D2-D4, indicate active sensitization due to the patch test. The objective of this study was to report our series of late patch test reactions. We analysed the clinical records of all the patients who had reported late reactions for the date of the late reaction, the results of the first patch tests and retesting. Between January 2002 and February 2006, we had a total of 16 patients with late reactions (>or=D10). 12 of them were retested. Retesting confirmed active sensitization to 1 or more allergens in 11 patients (1.3% of 884 patients patch tested). In these 11 cases, none of the late reactions had clear relevance to the symptoms before its appearance. The commonest allergens were paraphenylenediamine (PPD) in 6 patients (0.72% of 826 PPD tests), elecampane (Inula helenium) and black-eyed Susan (Rudbeckia sp. hybr.) extracts in 3 patients, and 4-aminoazobenzene and Disperse Orange 3 in 2 patients. The late reaction did not generally affect the clinical course. Only 1 patient developed new dermatitis possibly due to active sensitization. Late reactions meeting the classic criteria of active sensitization were relatively common in our series from a special clinic of occupational dermatology.

Retrospective evaluation of the consequence of alleged patch test sensitization

The risk of actively sensitizing a patient in connection with diagnostic patch tests exists. This risk, however, is extremely low, especially from standard allergens, and if the test is carried out according to internationally accepted guidelines. This retrospective study investigates the clinical consequences in cases of possible patch test sensitization. Among 7619 consecutively tested eczema patients in a 14-year period 26 (0.3%) were identified in the database as having had a late patch test reaction, which may be an indication of patch test sensitization. 9 of these cases were not suitable or available for the follow-up investigation and 3 patients were not traceable. Among the 14 remaining patients 1 had a reaction to gold sodium thiosulphate, which was assessed to be a persistent reaction and not a late reaction, and in 2 patients a clear relevance for the late reacting allergen was found. For the remaining 11 patients we could not rule out that they were patch test sensitized, and they were investigated further. 1 was diseased and 10 were interviewed regarding the possible consequences of the alleged patch test sensitization. 9 had not experienced any dermatitis problems, and 1 could not exclude the possibility that the alleged patch test sensitization had aggravated her dermatitis problems, although we find it unlikely based on the full clinical history. Even though the patient material is small and the limitations inherent in such a retrospective study, the results and the literature indicate that development of clinical contact dermatitis following patch test sensitization is very rare.

Contact allergy to herbal teas derived from Asteraceae plants

Contact allergy to herbal teas derived from the Asteraceae plant family was investigated in patients allergic to sesquiterpene lactones (SLs). 20 patients with a known contact allergy to SLs were recalled and patch tested with aqueous extracts of 8 different herbal teas based on Asteraceae plants as well as with parthenolide and other SLs. In 18 of 20 patients with SL allergy, there were positive test reactions to the Asteraceae teas, mainly to those based on German chamomile, dandelion and wormwood. Among the SLs, parthenolide was the most frequent co-reactor. Obviously, most patients with a contact allergy to SLs are allergic to commercial teas derived from the Asteraceae plant family as well.

The development and course of patch-test reactions to 2-hydroxyethyl methacrylate and ethyleneglycol dimethacrylate

Because Methacrylic monomers are used in dental work, dental personnel, technicians, and patients are at risk of being sensitized. 2-hydroxyethyl methacrylate (2-HEMA) and ethyleneglycol dimethacrylate (EGDMA) are commonly used. Allergic test reactions to them sometimes appear beyond D7. This study was designed to study the development and course of positive test reactions to 2-HEMA and EGDMA in allergic patients as a mean to elucidate the issue of patch-test sensitization. 12 patients with contact allergy to 2-HEMA and EGDMA were retested with dilution series. The clinical course was followed for 1 month. During the study, 25 positive test reactions to 2-HEMA and 19 to EGDMA were diagnosed. Within the 1st week, 21 were noted for 2-HEMA and 18 for EGDMA. After 10 days, another 2 reactions appeared for 2-HEMA and 1 for EGDMA. All but 1 patient with the latter reactions also had positive reactions within the 1st week. After 1 month, 12 reactions for 2-HEMA and 10 for EGDMA remained. Patch-test reactions to 2-HEMA and EGDMA are long-lasting. The patch-test concentrations of 2.0% for 2-HEMA and EGDMA may be continually used. Positive test reactions emerging after 10 days do not automatically imply active sensitization.

Gold trichloride and gold sodium thiosulfate as markers of contact allergy to gold

The usefulness of a trivalent gold salt, gold trichloride (GTC), was evaluated as a marker of contact allergy to gold. Patients patch test-positive or patch test-negative to gold sodium thiosulfate (GSTS), 13 subjects of each, were patch tested with dilution series of GTC and equimolar concentrations of GSTS. In order to avoid false-positive and false-negative test reactions, the salts were buffered and placed on polypropene chambers. Allergic reactions were registered in 9/13 gold-allergic patients with GSTS and in 2/13 with GTC. The sum of positive reactions was 18 with GSTS and 5 with GTC. Irritant reactions were none with GSTS and 2 with GTC in the gold-allergic patients. It is concluded that GTC can elicit positive patch test reactions in patients with gold allergy but to a lesser degree when compared with GSTS. Thus, GTC cannot be recommended in patch testing, and GSTS is still the test agent of choice.

Percutaneous absorption of gold sodium thiosulfate used for patch testing

Contact allergy to gold has been shown to be correlated to wearing of golden jewellery as well as to the presence of dental gold. The prerequisite for sensitization and elicitation of an allergic contact dermatitis to gold is ionization and percutaneous absorption of the allergen. The present study was undertaken with the aim to demonstrate gold in blood after an occlusive patch testing with gold sodium thiosulfate (GSTS). Patients were patch tested with GSTS 0.5, 2.0 and 5.0% in petrolatum. Venous blood was sampled before testing as well as on day 3 (D3) or day 7 (D7). Blood gold levels were analysed by inductively coupled plasma mass spectrometry. In all 66 patients, the blood level of gold was significantly higher in the 2nd blood sample than in the 1st (median 0.34 versus 0.03 micro g/l). The increase was similar in patients allergic and not allergic to gold. There was no difference between gold levels on D3 and on D7 after epicutaneous application. Presumably, other allergens may also be taken up in blood during patch testing.