Managing the excited skin syndrome: patch testing hyperirritable skin

Multiyear Group and Medical Center Patch Test Frequency Data: Confounding Variables

Patch test frequency data have been extensively published by research groups, such as the International Contact Dermatitis Research Group, North American Contact Dermatitis Group, Dermato-Allergology Study and Research Group, and European Environmental Contact Dermatitis Research Group. As this knowledge accumulation is widely applied in clinical and public health settings, we describe confounding factors to consider when using such data for medical policy considerations. These concepts can also be used in individual reports of new allergens or series of cases. Some of these confounders may have been reported in current literature (until October 2020), whereas others have not been mentioned/considered in most group publications.

Draize human repeat insult patch test (HRIPT): Seven decades of pitfalls and progress

Allergic contact dermatitis, a Type IV delayed hypersensitivity reaction, can result in dermatologic signs/symptoms for patients/workers. The likelihood of this phenomenon has been estimated/predicted for numerous chemicals/drugs by animal model and human patch testing protocols developed over the last century. Karl Landsteiner initiated testing with guinea pig studies; further studies based on his initial concept were in continual development. John Draize extended Landsteiner's guinea pig studies (which led to development of blood transfusions) to a human assay documenting irritant and allergic contact dermatitis potential - for drugs, chemicals, mixtures and products. We performed a literature search of major Draize derived protocols of the human repeat insult patch test (HRIPT). Our results reveal minor and major differences between protocols and lack of international standardization. Key clarification and principles post-Draize modified and improved usefulness of the HRIPT. Without a standard method of performing the HRIPT, it is problematic to generalize results of studies summarized here. Furthermore, we suggest a potential standardization procedure/protocol combining the work of the most satisfactory HRIPT methods. As the HRIPT constitutes a key parameter in current quantitative risk assessment for chemicals/drugs, such standardization should aid potential prediction of allergic contact dermatitis potential.

The Importance of Education When Patch Testing

Education is the keystone of successful management of allergic contact dermatitis. This article outlines practical tips to manage patients' expectations of the patch test process and understand their results. The considerations are outlined in a stepwise fashion from before, during, and after patch testing. Resources for patient information are highlighted, and an update on provider education is also included.

Novel metal allergy patch test using metal nanoballs

BACKGROUND

Patch tests are often used in the clinical diagnosis of metal allergies. In currently available patch tests, high concentrations of metal salt solutions are used. However, diagnosis accuracy can be influenced not only by acute skin reactions to high concentrations of metal salt, but also by skin reactions to other components present in the patch or to pH changes. In this study, we developed Ni nanoparticles (termed "nanoballs") for use in patch-test solutions.

FINDINGS

Highly soluble, spherical Ni nanoballs were prepared using plasma electrolysis. The Ni released from the nanoballs permeated through a dialysis membrane, and the nanoball-containing solution's pH was maintained constant. Ni ions were released slowly at low concentrations in a time-dependent manner, which contrasted the rapid release observed in the case of a commercial patch test. Consequently, in the new test system, reactions caused by high concentrations of metal salts were avoided.

CONCLUSIONS

By exploiting the high specific surface area of Ni nanoballs, we obtained an effective dissolution of Ni ions that triggered Ni allergy in the absence of direct contact between the nanoballs and mouse skin. This novel patch system can be applied to other metals and alloys for diagnosing various types of metal-induced contact dermatitis.

Reproducibility of food atopy patch tests over time in the general child population

BACKGROUND

The atopy patch test (APT) is no longer an experimental method; it is increasingly being used as a standard diagnostic tool for the characterization of patients with aeroallergen- and food-triggered disorders. Some technical aspects of this test still remain to be answered. We aimed to study the reproducibility of this test over time in the general child population.

METHODS

In a general population of 118 children, we investigated the reproducibility of duplicate APTs with four food allergens in their native form, which were repeated at set intervals from the first test: 7 days (group 1), 14 days (group 2), and 21 days (group 3).

RESULTS

We observed very poor reproducibility on both sides of the back in all three studied subgroups. The reproducibility rates and Cohen's kappa values did not improve when we did not consider the side of the back. There were no differences in the prevalence of atopy between the subjects with reproducible and nonreproducible APT results. All three groups studied showed no difference in the prevalence rates of atopy. There was no relationship between APT and skin prick test positivity for the same allergen. Questionnaire-derived data about previous food-related reactions did not help in the evaluation of the doubtful nonreproducible APT results with food allergens.

CONCLUSIONS

Our results show that the reproducibility of food APTs is poor and unsatisfactory over time, and there is an urgent need for the development of optimal, stable, and good-quality APT testing substances.

Mystery of the disappearing allergen: published allergens rarely seen again

Patch testing is an important tool in the diagnosis of allergic contact dermatitis. Although this technique can be accurate, occasionally the results may be inconclusive. A previously positive result to an allergen may become negative upon repeat testing, and this may complicate the process of achieving a definitive diagnosis. There are some potential explanations for such inconsistencies, including the Excited Skin Syndrome, irritant reactions, a need to repeat the diagnostic algorithm, "rogue" reactions, and "contact allergy." These explanations should be taken into account when interpreting these results. However, further knowledge is needed to solve the mystery of an allergen that subsequently disappears.

Atopy Patch Test – Reproducibility and Elicitation of Itch in Different Application Sites

We evaluated the reproducibility of atopy patch test reactions and the quality and quantity of itch in 16 patients with atopic eczema and a history of a positive atopy patch test reaction, comparing three different application sites. The allergen was re-applied simultaneously on both forearms and the back. Intensity and quality of pruritus were evaluated using a visual analogue scale and the Eppendorf itch questionnaire, respectively. The atopy patch test reaction was highly reproducible, occurring in 15/16 (94%) patients. Pruritus was reported by 14/16 (88%) patients. There was no significant difference in either the intensity or quality of itch between the two forearms and the back (p>0.05). The mean peak visual analogue scale itch score was comparable across all three test sites (range 28.3-31.9). Regarding quantification of test reactions, a positive reaction was more frequent on the back (94% versus 69% on the arms) and the peak atopy patch test score was higher on the back compared with the arms (right forearm, p=0.0018 and left forearm, p=0.0683). Allergens should preferably be applied on the back for the atopy patch test. However, the atopy patch test can induce atopic itch irrespective of the application site.

Copper hypersensitivity: dermatologic aspects--an overview

Reports of immune hypersensitivity reactions of both the immediate and the delayed type following cutaneous or systemic exposure to copper are reviewed here in an endeavor to draw a comprehensive profile of the immunogenic potential of that metal and its compounds. The immunotoxic potential of the metal is also briefly reviewed. In principle, as noted for other transition metals, the electropositive copper ion is potentially immunogenic because of its ability to diffuse through biological membranes, forming complexes when in contact with tissue protein. Based on the results of the predictive guinea pig test and the local lymph node assay (LLNA), copper has a low sensitization potential. Reports of immune reactions to copper include immunologic contact urticaria (ICU), allergic contact dermatitis (ACD), systemic allergic reactions (SAR) and contact stomatitis (STO), but considering the widespread use of copper intrauterine devices (IUDs) and the importance of copper in coinage, items of personal adornment and industry, unambiguous reports of sensitization to the metal are extremely rare, and even fewer are the cases that appear clinically relevant. Most reports of immune reactions to copper describe systemic exposure as a cause--predominantly to intrauterine devices and to prosthetic materials in dentistry--implicitly excluding the induction of hypersensitivity from contact with the skin as a risk factor.

Irritant contact dermatitis: is there an immunologic component?

Irritant contact dermatitis (ICD) describes a multifactorial disease resulting from exposure to occupational irritants. Though often characterized as a localized reaction, there are at least 10 forms of ICD, several of which possess systemic involvement. The exact mode of irritant action in ICD is not completely understood, but recent literature suggests that an immunologic-like component may be present. The correlation between the morphology, clinical manifestations and chemokines involved in allergic contact dermatitis and irritant contact dermatitis will be discussed and studies indicating an irritant "immunologic-like" response will be reviewed and analyzed.