BACKGROUND: The textile dye mix (TDM) 6.6% in petrolatum contains Disperse Blue (DB) 35, Disperse Yellow 3, Disperse Orange (DO) 1 and 3, Disperse Red 1 and 17, and DB 106 and 124. The most frequent allergen in TDM-positive patients is DO 3. Around 85% of para-phenylenediamine (PPD)-allergic dermatitis patients have been positive to DO 3. There has been a discussion to exclude DO 3 from TDM 6.6% because of strong simultaneous reactions to TDM and PPD.
OBJECTIVE: To study if DO 3 can be excluded from TDM 6.6%.
METHODS: Patch tests were performed on 1481 dermatitis patients with TDM 6.6%, TDM 7.0% (without DO 3 but the other disperse dyes at 1.0% each), DO 3 1.0%, and PPD 1.0% pet.
RESULTS: Contact allergy to TDM 6.6% was 3.6% and to TDM 7.0% was 3.0%. All 26 DO 3-positive patients were positive to PPD. The 44 patients positive to TDM 7.0% plus the 13 positive to PPD and TDM 6.6% but negative to TDM 7.0% were 57, outnumbering the 53 positive to TDM 6.6%.
CONCLUSIONS: TDM 7.0% can replace TDM 6.6% in the Swedish baseline series, since TDM 7.0% together with PPD 1.0% will detect patients with textile dye allergy.

The clinical usefulness of the atopy patch test (APT) is unclear for investigating aeroallergen- and food-triggered atopic dermatitis (AD).
This study aimed to assess the prevalence of positive APT reactions in a population of adolescents and investigate possible associations between the APT, specific serum (s) immunoglobulin E (IgE) tests, self-reported atopic conditions and health-related quality of life.
A population-based study was performed on 211 adolescents (13-14 years old). Collected data included questionnaires, an APT with food and aeroallergens and s-IgE tests.
Positive APT reactions were observed in 9.0% (19/211) of the adolescents. Timothy grass was the top allergen with 11 (5.2%) positive reactions, followed by cat dander (2.8%) and house dust mites (2.4%). Rhinoconjunctivitis increased the odds of any positive APT (crude odds ratio: 3.32; 95% confidence interval [CI]: 1.17–9.40), particularly when an APT was positive for aeroallergens (odds ratio: 5.02, 95% CI: 1.54-16.42). There was no association between a positive APT and AD. Four adolescents without AD and no IgE-sensitization had a positive APT.
Based on a population of adolescents, the APT is associated with rhinoconjunctivitis but not AD. This finding should be taken into consideration in further attempts to clarify the role of the APT in the clinical setting.

Hypersensitivity reactions (HRs) to contrast media (CM) are a major problem. We compared differences of HRs to iodinated contrast media (ICM) versus gadolinium-based contrast media (GBCM), collecting data on prevalence, type, latency and severity. Secondly, the predisposition to perform new contrast tests, use of premedication and possible appearance of new reactions were explored in a long-term follow-up of 5 years. Clinical data, comorbidities, skin test (ST) results, re-exposure to CM procedures with any new reactions, premedication and CM used were collected. In a retrospective single-center study, 350 patients with mild to moderate HRs were enrolled. Asthma, food allergy, non-allergic drug hypersensitivity and neurologic disease were significantly more frequent in patients with HRs to GBCM compared to the high evidence of cardiovascular disease and history of cancer in patients with HRs to ICM. A marked delay in performing STs was reported by patients with negative results (66 months, p < 0.01). Iomeprol, iopamidol and gadobenic acid were the culprit CM most involved in HRs in patients with positive STs. During follow-up, 7.1% of responders reported new HRs to CM despite negative STs, premedication and infusion of alternative CM in most cases.

The incidence of delayed injection site reaction after the first dose of mRNA-1273 vaccine was 12.5% among females and 1.5% among males in a cohort of primarily elderly Japanese. After the second dose, 48.4% of those who could be contacted reported recurrence. The reaction may be relatively common among Asian females.

Cutaneous reactions after messenger RNA (mRNA)-based COVID-19 vaccines have been reported but are not well characterized.
To evaluate the morphology and timing of cutaneous reactions after mRNA COVID-19 vaccines.
A provider-facing registry-based study collected cases of cutaneous manifestations after COVID-19 vaccination.
From December 2020 to February 2021, we recorded 414 cutaneous reactions to mRNA COVID-19 vaccines from Moderna (83%) and Pfizer (17%). Delayed large local reactions were most common, followed by local injection site reactions, urticarial eruptions, and morbilliform eruptions. Forty-three percent of patients with first-dose reactions experienced second-dose recurrence. Additional less common reactions included pernio/chilblains, cosmetic filler reactions, zoster, herpes simplex flares, and pityriasis rosea-like reactions.
Registry analysis does not measure incidence. Morphologic misclassification is possible.
We report a spectrum of cutaneous reactions after mRNA COVID-19 vaccines. We observed some dermatologic reactions to Moderna and Pfizer vaccines that mimicked SARS-CoV-2 infection itself, such as pernio/chilblains. Most patients with first-dose reactions did not have a second-dose reaction and serious adverse events did not develop in any of the patients in the registry after the first or second dose. Our data support that cutaneous reactions to COVID-19 vaccination are generally minor and self-limited, and should not discourage vaccination.

BACKGROUND: In Sweden, cobalt chloride 0.5% has been included in the baseline series since the mid-1980s. A recent study from Stockholm showed that cobalt chloride 1% petrolatum (pet.) was more suitable than 0.5%. Cobalt chloride at 1.0% has been patch tested for decades in many European countries and around the world.
OBJECTIVE: To study the suitability of patch testing to cobalt 1.0% vs 0.5% and to analyze the co-occurrence of allergy to cobalt, chromium, and nickel.
RESULTS: Contact allergy to cobalt was shown in 90 patients (6.6%). Eighty (5.9%) patients tested positive to cobalt 1.0%. Thirty-seven of the 90 patients (41.1%) with cobalt allergy were missed by cobalt 0.5% and 10 (0.7%) were missed by cobalt 1.0% (P < .001). No case of patch test sensitization was reported. Allergy to chromium was seen in 2.6% and allergy to nickel in 13.3%. Solitary allergy to cobalt without nickel allergy was shown in 61.1% of cobalt-positive individuals. Female patients had larger proportions of positive reactions to cobalt (P = .036) and nickel (P < .001) than males.
CONCLUSIONS: The results speak in favor of replacing cobalt chloride 0.5% with cobalt chloride 1.0% pet. in the Swedish baseline series, which will be done 2021.

BACKGROUND: Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and methylisothiazolinone (MI) are tested to detect contact allergy to these isothiazolinones.
OBJECTIVE: To study if an aqueous patch test preparation with MCI and MI in a mix of 0.015% and 0.2%, respectively, detects more contact allergies than the commonly used preparations of MCI/MI in 0.02% aq. and MI in 0.2% aq.
METHODS: A total of 1555 patients with dermatitis in five Swedish dermatology departments were tested consecutively with MCI/MI 0.215% aq., MCI/MI 0.02% aq., and MI 0.2% aq.
RESULTS: The share of contact allergy to MCI/MI 0.215% aq., MCI/MI 0.02% aq., and MI 0.2% aq. varied in the test centers between 7.9% and 25.9%, 3.2% and 10.3%, and 5.8% and 12.3%, respectively. MCI/MI 0.215% aq. detected significantly more patch-test positive individuals than both MCI/MI 0.02% aq. (P < .001) and MI 0.2% aq. (P < .001), as well as either one of MCI/MI and MI (P < .001). In the patients only reacting to MCI/MI 0.215% aq., 57.7% were recorded as having a dermatitis that was explained or aggravated by exposure to either MCI/MI or MI.
CONCLUSIONS: The results speak in favor of replacing the preparations MCI/MI 0.02% aq. and MI 0.2% aq. with MCI/MI 0.215% aq. as the screening substance in the Swedish baseline series, which has been implemented in 2020.

BACKGROUND: A fragrance mix consisting of eight separate fragrance ingredients (fragrance mix I [FM I]) is present in most baseline patch test series. Patch testing with the TRUE Test technique is considered to detect less contact allergy to FM I than testing with the Finn Chamber technique.
OBJECTIVE: To investigate the possible significance of batch and patch test method in establishing contact allergy to FM I.
METHODS: Three thousand one hundred and nineteen individuals representing a sample of the general population were patch tested with two batches of FM I with two patch test techniques at six dermatology clinics in five European countries. The TRUE Test technique and the Finn Chamber technique with pet. preparations were used. McNemar\'s test was used for statistical calculations.
RESULTS: The contact allergy prevalences varied between 0.7% and 2.6%. The patch tests with the mixes containing Evernia prunastri (oak moss) with a high content of chloratranol/atranol resulted in substantially more positive reactions than the corresponding tests with the mixes containing oak moss with a low content of chloratranol/atranol. The Finn Chamber technique detected significantly more contact allergic reactions than the TRUE Test technique (P < 0.001).
CONCLUSIONS: The Finn Chamber technique detects more contact allergy to FM I than the TRUE Test technique.

BACKGROUND: In 2014, the fragrance hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) was excluded from the Swedish baseline series.
OBJECTIVE: To study (i) whether fragrance mix (FM) II with 5% HICC detects more positive reactions than usual FM II with 2.5% HICC, and (ii) the reproducibility of patch testing with HICC.
METHODS: Two thousand one hundred and eighteen dermatitis patients at five Swedish dermatology departments were consecutively tested with FM II 14% pet., FM II 16.5% pet., and duplicate preparations of HICC 5% pet.
RESULTS: Of the patients, 3.2% reacted to FM II 14%, and 1.5% reacted to HICC. Separate testing with HICC detected 0.3% reactions without concomitant reactivity to FM II. FM II with 5% HICC did not give rise to more irritant reactions or signs of active sensitization than FM II with 2.5% HICC. Patch testing with duplicate applications of HICC increased the overall prevalence of HICC contact allergy to 1.9%.
CONCLUSIONS: FM II with 5% HICC does not detect more positive reactions than FM II with 2.5% HICC. Separate testing with HICC does not detect a sufficient proportion of patients who react only to HICC, without concomitant reactions to FM II, to warrant its inclusion in a baseline series.

BACKGROUND: Methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) are the active ingredients in commonly used preservative systems (e.g. Kathon CG(®)). MCI/MI is present in the European baseline patch test series at 100 ppm aq. Since 1986, 200 ppm (dose 0.006 mg/cm(2)) has been used in Sweden without causing skin irritation. Centres in Spain, the United Kingdom and Ireland have also used 200 ppm in their baseline series.
OBJECTIVE: To find the optimal patch test concentration for MCI/MI.
METHODS: MCI/MI 100 ppm aq. and MCI/MI 200 ppm aq. were simultaneously patch tested in 3300 consecutively tested dermatitis patients at eight European patch test clinics and one US patch test clinic. With the Finn Chambers(®) technique (diameter 8 mm), 15 µl was micropipetted on to the filter paper in the chamber. The corresponding volume for Van der Bend(®) chambers was 20 µl, and that for IQ Chambers(®) was 25 µl.
RESULTS: Contact allergy to MCI/MI at 100 and 200 ppm was found in 1.2% and 2.1% of patients, respectively (p < 0.001).
CONCLUSIONS: MCI/MI 200 ppm aq. (dose 0.006 mg/cm(2) ) diagnoses significantly more contact allergy than the presently used concentration of 100 ppm (dose 0.003 mg/cm(2)), without resulting in more adverse reactions. MCI/MI at 200 ppm should therefore be considered for inclusion in the European baseline test series.