Delayed Skin Testing for Systemic Medications: Helpful or Not?

Cutaneous adverse drug reactions collectively are delayed drug reactions such as morbilliform drug eruption and severe cutaneous adverse reactions (SCARs). Morbilliform drug eruption may wane over time, be the result of drug viral interactions, and be amenable to slow reintroduction or rechallenge, whereas SCARs are HLA class I restricted, T-cell-mediated reactions that demonstrate durable immunity and warrant lifelong avoidance. SCARs such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and generalized bullous fixed drug eruption often occur in the setting of multiple drugs dosed together. Collectively, they lead to significant morbidity, mortality, and drug safety concerns that could severely limit future treatment options. Currently, no single or combination of diagnostic tests for SCARs such as ex vivo or in vitro testing, in vivo (skin) testing, or other adjunctive tests such as HLA typing have 100% negative predictive value. In this "Controversies in Allergy Review" article, we review the current literature on delayed skin testing (patch and delayed prick/intradermal test) and critically assess the evidence base of its utility across different drugs and clinical phenotypes of delayed hypersensitivity reactions.

Comparison of patients with isolated cutaneous lupus erythematosus versus systemic lupus erythematosus with cutaneous lupus erythematosus as the sole clinical feature: A monocentric study of 149 patients.

BACKGROUND: Cutaneous lupus erythematosus (CLE) may present as an isolated entity or be classified as Systemic lupus erythematosus (SLE) by the presence of laboratory abnormalities, including cytopenia, low complement levels, and/or autoantibodies (CLE with laboratory SLE). OBJECTIVE: To compare isolated CLE and CLE with laboratory SLE and to validate an existing 3-item score with age < 25 years (1 point), phototypes V to VI (1 point), antinuclear antibodies ≥ 1:320 (5 points) to predict the risk of progression from CLE to severe SLE (sSLE). METHODS: Monocentric cohort study including consecutive patients with CLE. CLE with laboratory SLE was defined by 2019 American College of Rheumatology/European League Against Rheumatism classification criteria for SLE score of ≥10 points at baseline with CLE as the sole clinical feature. RESULTS: Of the 149 patients with CLE, 20 had CLE with laboratory SLE. The median follow-up duration was 11.3 years (IQR: 5.1-20.5). Ten patients (7%) had sSLE developed. In survival analysis, the risk of progression to sSLE was higher among CLE with laboratory SLE (hazard ratio = 6.69; 95% CI: 1.93-23.14, P < .001) compared to isolated CLE. In both groups, none of the patients with a risk score ≤ 2 had sSLE developed. LIMITATIONS: Monocentric study with a limited number of patients. CONCLUSIONS: CLE with laboratory patients with SLE have a higher risk of progression to sSLE than isolated CLE.

In Situ Patch Test and Repeated Open Application Test for Fixed Drug Eruption: A Multicenter Study.

BACKGROUND: Few studies have evaluated allergy workup in fixed drug eruption (FDE) in a large population. OBJECTIVE: To evaluate the sensitivity of a standardized allergy workup for diagnosing the cause of FDE, with a focus on in situ repeated open application tests (ROATs). METHODS: In a retrospective multicenter study, we analyzed the practice of conducting a complete allergy workup for the etiological diagnosis of FDE. It consisted of 3 steps: in situ patch tests (PTs) for all cases except pure mucosal involvement, followed by in situ ROAT if in situ PT results were negative, and finally a drug challenge (DC). The in situ ROAT involved daily application of the suspected drug on a previously affected FDE site for 7 days. RESULTS: Of 98 suspected FDE cases, 61 patients (median age 61 y; male-to-female ratio 1.8) with a complete allergy workup were included. In 4 cases, even the DC yielded negative results. Among the remaining 57 patients with a positive workup, implicated drugs included paracetamol (12 cases), ß-lactams (11 cases), imidazoles (9 cases, including 5 with metronidazole), nonsteroidal anti-inflammatory drugs (8 cases), iodinated contrast media (4 cases), cotrimoxazole (3 cases), and various other drugs in 10 patients. The diagnosis was confirmed by in situ PT in 17 of 54 cases (31.5%), in situ ROAT in 14 of 40 cases (35%) (with 4 cases showing remote reactivation of FDE sites), and DC in 26 cases. CONCLUSIONS: The sequential allergy workup involving successively in situ PT, in situ ROAT, and DC is a reliable and safe method for diagnosing the cause of FDE. In situ tests exhibited a sensitivity of over 50%.

Management of Adult Patients With Drug Reaction With Eosinophilia and Systemic Symptoms: A Delphi-Based International Consensus.

Importance: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but potentially fatal drug hypersensitivity reaction. To our knowledge, there is no international consensus on its severity assessment and treatment. Objective: To reach an international, Delphi-based multinational expert consensus on the diagnostic workup, severity assessment, and treatment of patients with DRESS. Design, Setting, and Participants: The Delphi method was used to assess 100 statements related to baseline workup, evaluation of severity, acute phase, and postacute management of DRESS. Fifty-seven international experts in DRESS were invited, and 54 participated in the survey, which took place from July to September 2022. Main Outcomes/Measures: The degree of agreement was calculated with the RAND-UCLA Appropriateness Method. Consensus was defined as a statement with a median appropriateness value of 7 or higher (appropriate) and a disagreement index of lower than 1. Results: In the first Delphi round, consensus was reached on 82 statements. Thirteen statements were revised and assessed in a second round. A consensus was reached for 93 statements overall. The experts agreed on a set of basic diagnostic workup procedures as well as severity- and organ-specific further investigations. They reached a consensus on severity assessment (mild, moderate, and severe) based on the extent of liver, kidney, and blood involvement and the damage of other organs. The panel agreed on the main lines of DRESS management according to these severity grades. General recommendations were generated on the postacute phase follow-up of patients with DRESS and the allergological workup. Conclusions and Relevance: This Delphi exercise represents, to our knowledge, the first international expert consensus on diagnostic workup, severity assessment, and management of DRESS. This should support clinicians in the diagnosis and management of DRESS and constitute the basis for development of future guidelines.

Hypersensitivity reactions to proton pump inhibitors. An EAACI position paper.

Proton pump inhibitors (PPIs) are invaluable therapeutic options in a variety of dyspeptic diseases. In addition to their well-known risk profile, PPI consumption is related to food and environmental allergies, dysbiosis, osteoporosis, as well as immediate and delayed hypersensitivity reactions (HSRs). The latter, although a rare event, around 1%-3%, due to the extraordinarily high rate of prescription and consumption of PPIs are related to a substantial risk. In this Position Paper, we provide clinicians with practical evidence-based recommendations for the diagnosis and management of HSRs to PPIs. Furthermore, the unmet needs proposed in the document aim to stimulate more in-depth investigations in the topic.

EAACI/ENDA position paper on drug provocation testing.

In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources.

Assessing delayed penicillin hypersensitivity using the PENFAST+ score.

Introduction: Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy. Objectives: The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value. Methods: STEP 1: Retrospective evaluation of the PEN-FAST score in patients with proven immediate and delayed penicillin allergy. STEP 2: Identification of additional criteria among Step 1 patients misclassified by PEN-FAST score. Development of the PEN-FAST+ score using multivariable logistic regression in a prospective cohort of patients with a suspicion of HS to penicillin. STEP 3: Comparison of diagnostic performances of PEN-FAST and PEN-FAST+ scores. Results: The PEN-FAST score showed limitations in predicting the relapse of immediate skin HS or delayed maculopapular exanthema, with 28.6% and 38.4% of patients misclassified, respectively. We identified two potential additional criteria: skin rash lasting more than 7 days and immediate reaction occurring in less than 1 h (generalized or localized on palmoplantar area or scalp itching/heat feeling). A total of 32/252 (12.7%) patients were confirmed to be allergic to penicillin. With PEN-FAST, 37% of patients (n = 10) with delayed allergic penicillin HS were misclassified. With PEN-FAST+, 3 patients with delayed HS confirmed by a ST (11.1%) were misclassified. The AUC was significantly higher for PEN-FAST+ than PEN-FAST (85% vs. 72%, p = 0.03).

Allergic contact dermatitis from essential oil in consumer products: Mode of uses and value of patch tests with an essential oil series. Results of a French study of the DAG (Dermato-Allergology group of the French Society of Dermatology).

OBJECTIVE: To analyse the clinical characteristics and sensitivity of an essential oil patch test series (EOS) in patients sensitized to their own essential oils (EOs). METHOD: We analysed the clinical data and patch test results obtained with the European baseline series (BSE) and an EOS, as well as the mode of use of EOs, through a questionnaire included in the patient file. RESULTS: The study included 42 patients (79% women, average age 50 years) with allergic contact dermatitis (ACD), 8 patients required hospitalization. All patients were sensitized to the EO they used, primarily lavender (Lavandula augustifolia, 8000-28-0), tea tree (Melaleuca alternifolia leaf oil, 68647-73-4), ravintsara (Cinnamomum camphora oil, 92201-50-8), and 2 cases were attributed to helichrysum (helichrysum italicum flower absolute, 90045-56-0). 71% had positive patch tests to fragrance mix I or II, 9 only to the EOS and 4 only with their personal EO. Interestingly, 40% of patients did not spontaneously mention the use of EOs, and only 33% received advice on their use at the time of purchase. CONCLUSION: Patch tests with the BSE, limonene and linalool HP, and oxidized tea tree oil is sufficient to detect most EO-sensitized patients. The most important is to test the patient's own used EOs.

Hand eczema in glove-wearing patients.

BACKGROUND: Allergic contact dermatitis to gloves is mostly induced by rubber accelerators. The European baseline series (EBS) appears insufficient to detect glove allergy. Since 2017, it is recommended to use the European rubber series (ERS) and to test the patients' own gloves. OBJECTIVES: To investigate the clinical profile of glove-wearing patients with hand eczema (HE) and to evaluate their sensitisation profile to glove allergens and the value of testing the patients' own gloves. METHODS: We conducted a French multicentre study of patients evaluated for HE between 2018 and 2020 and tested with the EBS, the ERS and their own gloves in patch tests and semi-open (SO) tests. RESULTS: A total of 279 patients were included; 32.6% of patients had positive tests to their own gloves or to glove allergens. Almost 45% of the sensitisations to glove allergens were detected only by the ERS. Among the patients tested both in patch tests and SO tests with their own gloves with positive results, 28% had positive SO tests only. Polyvinylchloride (PVC) gloves were positive in four patients. CONCLUSION: Our series confirms the need to test the ERS. All the patients' gloves must also be tested including PVC gloves. SO tests with gloves are useful as a complement to patch tests.