Patch Testing With Nickel Sulfate 5.0% Traces Significantly More Contact Allergy Than 2.5%: A Prospective Study Within the International Contact Dermatitis Research Group.

BACKGROUND: Nickel allergy is the most common contact allergy, and a nickel salt is, therefore, included in most baseline patch test series. In the baseline series of the International Contact Dermatitis Research Group and the American Contact Dermatitis Society, nickel sulfate hexahydrate (NSH) in petrolatum at 2.5% is included, whereas NSH at 5.0% is included in many other baseline series, such as the European and Swedish ones. OBJECTIVE: The aim of the study is to investigate whether NSH at 5.0% detects significantly more contact allergy than NSH 2.5% when both preparations are tested simultaneously in consecutive dermatitis patients. PATIENTS AND METHODS: Two thousand two hundred eighty-seven consecutive dermatitis patients were patch tested simultaneously with NSH in petrolatum at 2.5% and 5.0%. The allergy rates were compared for all clinics individually and combined using McNemar test, 2-sided. RESULTS: Contact allergy to NSH 5.0% and 2.5% was found in 20.3% and 16.8%, respectively ( P < 0.0001). In 6 of 11 clinics, significantly more patients tested positive to the higher NSH concentration. For the 2 clinics in North America combined, significantly more patients tested positive to NSH 5.0%. CONCLUSIONS: The NSH preparation in the International Contact Dermatitis Research Group baseline patch test series should be considered to be changed from NSH 2.5% (1 mg NSH/cm 2 ) to 5.0% (2 mg NSH/cm 2 ).

Patch Testing With a New Composition of the Mercapto Mix-A Multicenter Study from the International Contact Dermatitis Research Group.

BACKGROUND: Mercaptobenzothiazole compounds are associated with allergic contact dermatitis caused by rubber products. Several screening substances have been used for patch testing. OBJECTIVE: To compare the frequency of positive test reactions to a mercapto mix containing a higher concentration of 2-mercaptobenzothiazole with reactions to the combination of 2-mercaptobenzothiazole 2.0% and mercapto mix 2.0%. METHODS: There were 7103 dermatitis patients in 12 International Contact Dermatitis Research Group dermatology departments who were patch tested with 2-mercaptobenzothiazole 2.0% petrolatum (pet.), mercapto mix 2.0% pet., and mercapto mix 3.5% pet. RESULTS: Contact allergy to the 3 test preparations varied among the 12 centers: 2-mercaptobenzothiazole 2.0% pet. (0-2.4%), mercapto mix 2.0% pet. (0-4.9%), and mercapto mix 3.5% pet. (0-1.4%). 2-Mercaptobenzothiazole 2.0% and mercapto mix 2.0% detected a few more positive patients compared with mercapto mix 3.5%, but the difference was statistically insignificant (mercapto mix 2.0% pet., P = 1.0; 2-mercapto-benzothiazole 2.0% pet., P = 0.66). CONCLUSIONS: Mercapto mix 3.5% pet. is not better than 2-mercaptobenzothiazole 2.0% and mercapto mix 2.0% by a difference that is significant. By using only 1 test preparation (mercapto mix 3.5%), an additional hapten could be tested. No cases of suspected/proven patch test sensitization were registered.

Patch Testing With Methylchloroisothiazolinone/Methylisothiazolinone Using a New Diagnostic Mix-A Multicenter Study From the International Contact Dermatitis Research Group.

BACKGROUND: In the early 1980s, a preservative containing a mixture of methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) in a ratio of 3:1 was introduced. This mixture (mix) has been patch tested at 100 ppm (0.01%) worldwide and at 200 ppm (0.02%) in Sweden since 1986 and also in the European baseline series since 2014. OBJECTIVE: A new aqueous mix of MCI 0.015% and MI 0.2% was compared with patch testing with the 2 aqueous baseline preparations of MCI/MI 0.02% and MI 0.2%. METHODS: Four thousand three hundred ninety-seven patients with dermatitis in 12 International Contact Dermatitis Research Group dermatology departments from 3 continents were patch tested simultaneously with the 3 preparations. RESULTS: The frequency of positive patch tests to the allergens varied between 0% and 26.7% in the 12 test centers. The new mixture MCI/MI 0.215% in aqua (aq) detected significantly more patients with MCI/MI allergy than both MCI/MI 0.02% aq (P < 0.001) and MI 0.2% aq (P < 0.001) alone and combined. CONCLUSIONS: The results favor replacing the preparations MCI/MI 0.02% aq and MI 0.2% aq with the mixture MCI/MI 0.215% aq in the International Contact Dermatitis Research Group baseline series.

Contact Allergy to Fragrance Mix II and Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde: A Retrospective Study by International Contact Dermatitis Research Group.

BACKGROUND: Fragrance mix II (FM II) is included in the baseline patch test series recommended by the International Contact Dermatitis Research Group (ICDRG). Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is the most important sensitizer of the 6 fragrance materials included in FM II. Besides being a part of FM II, HICC is also tested separately in the ICDRG baseline series. OBJECTIVES: The aim of the study was to investigate the prevalence of contact allergy to FM II and HICC in 2012-2016 with a focus on simultaneous reactions and the percentage of missed contact allergy to HICC provided that only FM II had been tested. PATIENTS AND METHODS: A total of 25,019 consecutive dermatitis patients in 13 dermatology clinics representing 12 countries in 5 continents were patch tested with FM II and HICC in the baseline series. RESULTS: Contact allergy to FM II and HICC was found in 3.9% and 1.6%, respectively. For FM II, the frequency varied from 1.5% to 7.6% in different centers. The corresponding range for HICC was 0.2% to 3.6%. Simultaneous contact allergy to FM II and HICC was noted in 1.4% with the range 0.2% to 2.6%. Seventy-seven patients (0.31%) with contact allergy to HICC did not test positively to FM II. The range for missed HICC allergy by testing only FM II in the different centers would be 0.04% to 0.74%. The ratio between the contact allergy rates for FM II and HICC was similar for all centers, except for Montreal having significantly more contact allergy to FM II than to HICC. CONCLUSIONS: The frequency of missed contact allergy to HICC when testing only with FM II was less than 0.5%, therefore questioning the need to test HICC separately in the ICDRG baseline series.

Diagnosing Allergic Contact Dermatitis Through Elimination, Perception, Detection and Deduction.

Several authors have commented upon the skills of detection required in making a diagnosis of allergic contact dermatitis. Here, we emphasise the search for clues in a systematic manner. We describe four stages as part of a systematic method for diagnosing allergic contact dermatitis. Firstly, elimination (or inclusion) of non-allergic diagnoses. Secondly, perception: the pre-patch test diagnosis and the 'three scenarios' principle. Thirdly, detection: optimising the sensitivity of the patch test process. Fourthly, deduction: diagnosing allergic contact dermatitis by associating the dermatitis with the allergen exposure. We further compare and contrast the pre-patch test history and examination with the markedly different one ('microhistory' and 'microexamination') used after patch testing. The importance of knowledge of contact dermatitis literature is emphasised with a review of recent publications. Finally, we also highlight the use of contact allergy profiling as an investigative tool in the diagnosis of allergic contact dermatitis.

Disseminated Autochthonous Dermal Leishmaniasis Caused by Leishmania siamensis (PCM2 Trang) in a Patient from Central Thailand Infected with Human Immunodeficiency Virus.

AbstractSeveral case reports of autochthonous leishmaniasis in Thailand have been published since 1996. Most of the previous cases presented with visceral leishmaniasis (VL) and were mostly reported in southern part of Thailand. Recently, it has been evident that Leishmania martiniquensis is the main cause of Leishmania infection in Thailand. However, Leishmania siamensis (PCM2 Trang isolate) was found to be of a separate lineage with restricted distribution in southern Thailand and also a cause of disseminated dermal and visceral leishmaniasis in one published case. Here we report the first patient from central Thailand with human immunodeficiency virus infection presenting with disseminated dermal leishmaniasis. Polymerase chain reaction and DNA sequencing analysis (large subunit of RNA polymerase II and 18S ribosomal RNA internal transcribed spacer 1) from the tissue biopsy sample revealed the pathogen sequences to be highly homologous to PCM2 Trang strain previously reported from southern Thailand.

Proposed ICDRG Classification of the Clinical Presentation of Contact Allergy.

The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisting eczema, multifactorial dermatitis including allergic contact dermatitis, by proxy, mimicking angioedema, airborne contact dermatitis, photo-induced contact dermatitis, systemic contact dermatitis, noneczematous contact dermatitis, contact urticaria, protein contact dermatitis, respiratory/mucosal symptoms, oral contact dermatitis, erythroderma/exfoliative dermatitis, minor forms of presentation, and extracutaneous manifestations.

Fragrance allergy could be missed without patch testing with 26 individual fragrance allergens.

BACKGROUND: In 2003, the EU Cosmetics Directive stated that 26 fragrance substances must be listed on the cosmetic product ingredient labels. Not all of these 26 fragrance substances are detected by the usual screening markers comprising fragrance mix I, fragrance mix II, and Myroxylon pereirae. OBJECTIVES: To evaluate the usefulness of testing with the 26 individual fragrance substances in addition to the standard fragrance screening markers. MATERIALS AND METHODS: Three hundred and twelve consecutive patients were patch tested with our baseline series and the 26 specific fragrance substances required to be declared on cosmetic product ingredient labels in accordance with the EU Cosmetics Directive. RESULTS: Positive reactions to at least either one of the 26 individual fragrance substances or the usual fragrance screening markers were seen in 84 of 312 patients (26.9%). Fifteen of these 84 patients (17.8%) reacted negatively to the fragrance screening markers. The most common individual fragrance allergens were cinnamyl alcohol (11.2%), cinnamal (9%), and hydroxycitronellal (3.8%). Sixty-two of 312 patients (19.8%) had at least one positive reaction to the fragrance screening markers. CONCLUSION: Additional patch testing with the 26 individual fragrance allergens, or with the commonest fragrance allergens identified within these 26, should be performed to optimize the detection of fragrance allergy. Cinnamyl alcohol and cinnamal are important fragrance allergens in Thailand.

Methylchloroisothiazolinone/Methylisothiazolinone and methylisothiazolinone allergy.

BACKGROUND: Preservatives used in cosmetics tend to be, by their nature, allergenic. Methylisothiazolinone (MI) has been used as a sole preservative in multiple cosmetics, household goods, and toiletries. A current epidemic of MI has recently been reported in Europe. OBJECTIVE: The aim of this study was to study the prevalence of methylchloroisothiazolinone/MI (MCI/MI) and MI allergy in a Bangkok dermatology clinic. METHODS: During January 2009 to June 2014, 3253 consecutive patients tested with 100 ppm (0.01%) MCI/MI and patients tested with 2000 ppm (0.2%) MI were included in the study. RESULTS: Three hundred twenty of 3253 patients (9.8%) tested for MCI/MI had a positive reaction. There was a steep increase in the prevalence of MCI/MI contact allergy from 4.8% in 2009 to 11.2% in 2011 and 17% in 2013. In the first 6 months of 2014, 22 of 54 cases tested for MI (40.7%) had a positive reaction. Among those who had a positive reaction to MI, 6 of 22 (27.3%) showed negative reaction to MCI/MI. CONCLUSIONS: There is a similar prevalence of MI allergy in a Bangkok dermatology clinic as those reported in European centers such in the United Kingdom.

The cosmetic allergy conundrum: inference of an immunoregulatory response to cosmetic allergens.

The ability to be sensitized to experimental contact allergens declines significantly with increasing age, from as early as age 40 years. In contrast, the rate of contact allergy to chemical allergens (haptens) in cosmetic products significantly increases with age. This has been explained previously on the basis of greater cumulative exposure in the older age groups. However, outbreaks of contact allergy to preservatives in cosmetic products recorded soon after their introduction to the market have also shown a significantly higher rate among older adult age groups. This association with increasing age cannot be readily explained by exposure history or pattern, and is not compatible with a sensitizing/stimulatory reaction that degrades with age as the sole immune response. From this, the existence of a second, tolerizing/regulatory arm to the immune response to cutaneous haptens that possibly becomes less effective with age at a higher rate than the sensitizing/stimulatory arm can be inferred. This reinforces the view that current clinical and experimental observations of allergic contact dermatitis are best explained by an immune system with the functional ability to produce both sensitizing/stimulatory and tolerizing/regulatory responses.

Chemical atopy.

BACKGROUND: Although atopic disease is associated with protein allergy, its relationship with chemicals (haptens/contact allergens and irritants) is less clearly defined. The 'hapten-atopy' hypothesis, whereby significant hapten and irritant exposure during times of natural T helper (Th)2 bias (pregnancy and first year of life) promotes the development of atopy and atopic disease in the resulting child, has been previously proposed. Supporting evidence includes the practice of repeated cutaneous application of haptens in generating animal models of atopic dermatitis, and the observation of a significant increase in atopic disease in children born to mothers with occupations associated with high chemical exposure during pregnancy. OBJECTIVES: To observe the relationship between personal chemical exposure and atopic disease in a particular case series. METHODS: We report a case series of exacerbation of atopic dermatitis after repeated cutaneous chemical exposure. RESULTS: Most of the patients had atopic dermatitis in young childhood that had resolved. However, after repeated chemical exposure, either occupationally as an adult or after starting to use cosmetics as a teenager, there was clear exacerbation of atopic dermatitis. Patch tests gave negative results in most cases. CONCLUSIONS: We propose that repeated exposure to chemicals in patients with an atopic background can occasionally lead to reactivation of atopic dermatitis.