The necessity of a test reading after 1 week to detect late positive patch test reactions in patients with oral lichen lesions

A literature review and expert consensus statement on diagnostics in suspected metal implant allergy

BACKGROUND

Although rare, allergic reactions to metal implants represent a diagnostic challenge in view of missing guidelines.

OBJECTIVES

To develop an European expert consensus on characteristics of metal allergy reactions and the utility of various diagnostic tools in suspected metal implant allergy.

METHODS

A nominal group technique (NGT) was applied to develop consensus statements. Initially an online literature database was created on a secure server to enable a comprehensive information. Twenty-three statements were formulated on potential aspects of metal implant allergy with a focus on diagnostics and grouped into five domains. For the consensus development, the panel of 12 experts initially did refine and reformulate those statements that were ambiguous or had unclear wording. By face-to-face (9/12) or virtual participation (3/12), an anonymous online voting was performed.

RESULTS

Consensus (≥80% of agreement) was reached in 20/23 statements. The panel agreed that implant allergy despite being rare should be considered in case of persistent unexplained symptoms. It was, however, recommended to allow adequate time for resolution of symptoms associated with healing and integration of an implant. Obtaining questionnaire-aided standardized medical history and standardized scoring of patient outcomes was also considered an important step by all experts There was broad consensus regarding the utility/performance of patch testing with additional late reading. It was recognized that the lymphocyte transformation test (LTT) has to many limitations to be generally recommended. Prior to orthopaedic implant, allergy screening of patients without a history of potential allergy to implant components was not recommended.

CONCLUSIONS

Using an expert consensus process, statements concerning allergy diagnostics in suspected metal implant allergy were created. Areas of nonconsensus were identified, stressing uncertainty among the experts around topics such as preoperative testing in assumed allergy, histological correlate of periimplant allergy and in vitro testing, which underscores the need for further research.

Contact allergies to dental materials in patients

BACKGROUND

Concerns regarding contact allergies and intolerance reactions to dental materials are widespread among patients. Development of novel dental materials and less frequent amalgam use may alter sensitization profiles in patients with possible contact allergy.

OBJECTIVES

To analyse current sensitization patterns to dental materials in patients with suspected contact allergy.

METHODS

This retrospective, multicentre analysis from the Information Network of Departments of Dermatology (IVDK) selected participants from 169 834 people tested in 2005-2019 and registered with (i) an affected area of 'mouth' (and 'lips'/'perioral'), (ii) with the dental material in question belonging to one of three groups (dental filling materials, oral implants or dentures or equivalents) and (iii) with patch-testing done in parallel with the German baseline series, (dental) metal series and dental technician series.

RESULTS

A total of 2730 of 169 834 tested patients met the inclusion criteria. The patients were predominantly women (81.2%) aged ≥ 40 years (92.8%). The sensitization rates with confirmed allergic contact stomatitis in women (n = 444) were highest for metals (nickel 28.6%, palladium 21.4%, amalgam 10.9%), (meth)acrylates [2-hydroxyethyl methacrylate (HEMA) 4.8%] and the substances propolis (6.8%) and 'balsam of Peru' (11.4%). The most relevant acrylates were HEMA, 2-hydroxypropyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate and pentaerythritol triacrylate. Few men were diagnosed with allergic contact stomatitis (n = 68); sensitization rates in men were highest for propolis (14.9%) and amalgam (13.6%).

CONCLUSIONS

Allergic contact stomatitis to dental materials is rare. Patch testing should not only focus on metals such as nickel, palladium, amalgam and gold, but also (meth)acrylates and the natural substances propolis and 'balsam of Peru'.

Immunological Mechanisms of Metal Allergies and the Nickel-Specific TCR-pMHC Interface

Besides having physiological functions and general toxic effects, many metal ions can cause allergic reactions in humans. We here review the immune events involved in the mediation of metal allergies. We focus on nickel (Ni), cobalt (Co) and palladium (Pd), because these allergens are among the most prevalent sensitizers (Ni, Co) and immediate neighbors in the periodic table of the chemical elements. Co-sensitization between Ni and the other two metals is frequent while the knowledge on a possible immunological cross-reactivity using in vivo and in vitro approaches remains limited. At the center of an allergic reaction lies the capability of a metal allergen to form T cell epitopes that are recognized by specific T cell receptors (TCR). Technological advances such as activation-induced marker assays and TCR high-throughput sequencing recently provided new insights into the interaction of Ni2+ with the αβ TCR-peptide-major histocompatibility complex (pMHC) interface. Ni2+ functionally binds to the TCR gene segment TRAV9-2 or a histidine in the complementarity determining region 3 (CDR3), the main antigen binding region. Thus, we overview known, newly identified and hypothesized mechanisms of metal-specific T cell activation and discuss current knowledge on cross-reactivity.

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.

Value of photo assessment in late patch test readings-A multicenter study from six European patch test clinics

BACKGROUND

It is recommended that patch test readings include a day (D)7 reading. Substitution of the D7 reading with a photo may be a valid option.

OBJECTIVES

To compare the sensitivity of digital photos at D7 to clinical readings, to assess the number of positive reactions appearing at D7 only (late reactions), and after D7 only (delayed reactions).

METHODS

Patients patch tested in six European clinics were instructed to forward photos of the patch test reactions to the respective clinics at D7 (before attending the clinic) and at D21. Only allergens in the baseline series or TRUE Test were included in the data analysis.

RESULTS

Two hundred ninety-three of 629 patients had a total of 599 positive reactions, with 6.3% occurring at D7 only. When substituting the D7 reading with a photo (90% submitted), 26.3% of late reactions were missed and nine false-positive reactions were found. Delayed reactions were detected in four patients at D21 (65.3% submitted).

CONCLUSION

Our data show that if the D7 reading is not performed, 6.3% of positive reactions from the baseline series would be missed, and if substituting the D7 reading by digital photo, 26.3% late reactions would be missed. Delayed reactions seemed rare.

Pitfalls in Patch Testing: Minimizing the Risk of Avoidable False-Negative Reactions

Patch testing is the gold-standard diagnostic tool for the diagnosis of allergic contact dermatitis; unfortunately, it is a procedure with potential for errors, including false-negative reactions. Some of the factors responsible for this are likely unavoidable; however, others may potentially lie within the control of the user. Knowledge and management of these controllable factors may improve the outcome of patch testing and minimize the incidence of false-negative patch test results.

COMMON ALLERGIES AND ALLERGENS IN ORAL AND PERIORAL DISEASES

Allergic reactions sometimes participate in the development of perioral and oral diseases, indicating the need for appropriate allergen assessment. This review discusses current knowledge on the potential allergic reactions to different dental materials in patients with oral and perioral diseases. Aside from allergies to various dental materials, similar non-allergic, non-immune contact reactions (irritant or toxic) can occur. Among dental materials, the most frequent allergens are alloys, followed by rubber materials, polymers and acrylates. Allergic reactions to dental alloys that contain nickel, cobalt and amalgam are especially frequent since dentists use them for prosthetic and other restorations. There is a broad spectrum of clinical presentations of oral and perioral diseases possibly related to allergies, such as lichenoid reactions, cheilitis, perioral dermatitis, burning sensations, etc. Despite some limitations, patch test is crucial in the diagnosis and recognition of causative allergens because it reveals contact allergies, and is still superior in differentiating allergic and irritant contact reactions. It is important to examine patient medical histories (e.g., occurrence of symptoms after dental therapy or food consumption), and in consultation with their dentist, carry out allergy tests to specific dental allergens which are used or planned to be used in subsequent treatment.

The Final Patch Test Read: Day 5 or Day >7?

BACKGROUND

A major question in patch testing is when to perform the final reading. Our current standard practice is to place patches on day 1, remove them on day 3, and perform readings on days 3 and 5. For certain allergens, another reading is performed sometime from days 7 to 14≥.

OBJECTIVES

The aim of the study was to identify allergens with positive reactions on day 5 that were negative on day 7 or later and allergens with negative reactions on day 5 that were subsequently positive on day 7 or later.

METHODS

We reviewed records of patients who underwent patch testing from January 2007 to December 2016 at Mayo Clinic with readings on day 5 and day 7 or later.

CONCLUSIONS

In total, 131 allergens had positive reactions on day 5 that were negative on day 7 or later, and 58 allergens had negative reactions on day 5 that were positive on day 7 or later. Twenty-five allergens had significantly higher reaction rates on day 5 than day 7 or later. Our standard practice is to perform readings on days 3 and 5 and on days 3, 5, and 7 or later for series containing metals. Readings on days 3, 5, and 7 or later should also be considered for acrylates.

New positive patch test reactions on day 7-The additional value of the day 7 patch test reading

BACKGROUND

Not performing a day (D) 7 patch test reading might result in positive patch test reactions being missed.

OBJECTIVES

To investigate the added value of the D7 patch test reading for individual allergens, and to identify patient characteristics and allergen groups associated with new positive D7 reactions.

METHODS

Data from patients patch tested between 2008 and 2018 with the extended European baseline series were analysed. Patch test readings were performed on D3 and D7. Positive reactions were categorized into positive on D3 or new positive on D7.

RESULTS

A total of 3292 patients were consecutively patch tested with at least 43 allergens of the TRUE Test panels 1 and 2 supplemented with investigator-loaded allergens. In total, 447 (13.6%) patients showed new positive D7 reactions. In univariable regression analysis, age between 18 and 30 years showed a negative association with new positive D7 reactions. Significantly more D7 positive reactions were seen for topicals (odds ratio [OR] 2.60, 95% confidence interval [CI]: 1.92-3.51) and corticosteroids (OR 1.87, 95%CI: 1.09-3.21). No associations were found between sex, atopic dermatitis and occupational dermatitis and a new positive D7 reaction.

CONCLUSION

A D7 reading to identify new positive patch test reactions is of added value, especially for topicals and corticosteroids.