Negative Patch Test Research Articles

Reticular Telangiectatic Erythema in Association to Implanted Medical Device

Infections associated with implantable devices pose significant risks, as bacteria and other microorganisms can attach to the device surfaces, leading to complications ranging from mild inflammation to severe, potentially fatal infections. This review explores the development of reticular telangiectatic erythema (RTE) in patients with various implanted medical devices, including subcutaneous neurostimulators, shoulder prostheses, and hip prostheses. RTE manifests as red, net-like patches on the skin covering the device and is often associated with low-grade infections caused predominantly by Staphylococcus epidermidis, known for its biofilm-forming capability. The review presents three cases of RTE following device implantation, all resolving after antimicrobial treatment and device removal, despite negative patch tests for contact allergies. These cases highlight the importance of recognizing low-grade infections in patients with implanted devices and underscore the need for precise diagnostic and therapeutic strategies. The findings suggest that infections involving S. epidermidis play a critical role in the development of RTE. This review stresses the importance of preventive measures such as meticulous implantation techniques and prophylactic antibiotics and advocates for further research with larger sample sizes to better understand the role of microorganisms in RTE. It also calls for the development of improved diagnostic and treatment strategies. Future research directions include creating new materials resistant to biofilm formation, developing advanced antimicrobial agents, and enhancing diagnostic techniques to detect infections earlier.

Exploring antibiotic safety: A prospective observational study from a tertiary care public sector hospital

BackgroundAntibiotics are the most commonly used drugs to treat bacterial infections; however, these life-saving drugs can also cause adverse drug reactions. In several pharmacovigilance studies, adverse drug reactions are a cause of prolonged hospitalization. The development of hypersensitivity reactions even after a negative skin test and patch test makes antibiotic-associated adverse reactions unpredictable. Owing to the scarcity of data on antibiotic desensitization, these drugs are important for pharmacovigilance. Most of the previous studies conducted were retrospective and lacked data regarding the duration of adverse drug reactions. AimThis study aimed to examine adverse drug reactions associated with antibiotics and to provide knowledge on the duration of these reactions. MethodA prospective observational study was conducted on patients receiving antibiotics at a tertiary care hospital. The patients were followed until discharge, and causality and severity assessments were performed. Descriptive statistical analyses were performed to summarize the data. ResultsThe study results show the median duration of adverse drug reactions was two days, with an interquartile range of two to four days. Most (21,3%) of the reactions were caused by cephalosporins. The majority (44.7%) of the reactions were skin and subcutaneous tissue disorders. The majority (78.7%) of the reactions were moderately severe and were not responsible for prolonged hospital stay. ConclusionThe patients receiving antibiotics require close monitoring for early detection and management of adverse reactions to reduce the duration of hospital stay and the duration of adverse drug reactions.

Allergic Contact Dermatitis to Linalool Hydroperoxides: Pitfalls in the Diagnostic Process-Findings from a Repeated Open Application Test Study.

Background: Increasing trends of oxidized linalool contact allergy have been reported. However, the impact of reactivity and dose in eliciting allergic contact Dermatitis caused by linalool hydroperoxides is insufficiently investigated. Objectives: To perform repeated open application tests (ROATs) using the real-world concentrations of linalool hydroperoxides in patients and control participants. Materials and Methods: Patients who previously had a positive (patients) and a negative (controls) patch test reaction to linalool hydroperoxides 1.0% in petrolatum were patch tested with a dilution series of linalool hydroperoxides preparations and asked to perform ROAT twice daily with 3 concentrations of linalool hydroperoxides creams and a negative control cream for 28 days. The creams contain 44, 140, and 440 PPM of linalool hydroperoxides, representing real-world doses reported in consumer products. Results: Of all 47 participants, 31 were linalool hydroperoxides contact allergy patients, and 16 were controls. One patient had a positive ROAT reaction in the area where cream at the highest concentration of linalool hydroperoxides was applied for 28 days. Conclusions: Repeated exposure to creams containing linalool hydroperoxides at real-life concentrations could rarely elicit an allergic reaction on intact skin after 4 weeks.

Diagnostic accuracy of patch testing based in clinical response to contact allergen restrictions in allergic contact dermatitis.

Background. Patch testing (PT) is used to identify substances that cause allergic contact dermatitis (ACD). However, the clinical effects of allergen restrictions following PT have not been thoroughly investigated. This study aims to assess the diagnostic accuracy of PT in patients suspected of having ACD. Methods. Prospective study. PT were performed in patients with clinical diagnosis of ACD. Patients with a positive PT (case group) had a strict restriction of the suspected substance for one month. In patients with negative patch testing (control group), allergen restriction was based in clinical history. Clinical reduction (CR) of at least 50% in disease activity (CR50%) after one month of allergen restriction was considered clinically relevant. Total control was defined as clinical reduction of at least 90% (CR90%). Results. From 400 patients, 66.2% had a positive PT. The sensitivity of PT to identify CR50% was 84%, specificity 47%, PPV 53%, and NPV 81%. Only 10.5% of patients achieved CR90%. Conclusions. The PT had moderate diagnostic accuracy. It could be useful as a screening, but a positive result should be confirmed with controlled allergen restriction. The low number of patients who achieved a 90% CR invites to reconsider the allergens included in PT and the mechanistic processes of the disease.

Regulation of immune response genes in the skin of allergic and clinically tolerant individuals exposed to p-phenylenediamine.

p-Phenylenediamine (PPD) is a potent contact allergen found in many hair colour products. However, not all individuals develop allergic contact dermatitis (ACD) although they are regularly exposed to PPD. It is unclear whether these asymptomatic individuals are true non-responders to PPD or whether they mount a response to PPD without showing any symptoms. Skin biopsies were collected from 11 asymptomatic hairdressers regularly exposed to PPD and from 10 individuals with known ACD on day 4 after patch testing with 1% PPD in petrolatum and petrolatum exclusively as control. RNA sequencing and confocal microscopy were performed. T cell activation, inflammation and apoptosis pathways were up-regulated by PPD in both asymptomatic and allergic individuals. Compared to asymptomatic individuals with a negative patch test, individuals with a strong reaction to PPD strongly up-regulated both pro- and anti-inflammatory cytokines genes. Interestingly, PPD treatment induced significant up-regulation of several genes for chemokines, classical type 2 dendritic cell markers and regulatory T cell markers in both asymptomatic and allergic individuals. In addition, apoptosis signalling pathway was activated in both non-responders and allergic individuals. This study demonstrates that there are no true non-responders to PPD but that the immune response elicited by PPD differs between individuals and can lead to either tolerance, subclinical inflammation or allergy.

Metal allergy and neurovascular stenting: A systematic review.

Intracranial stents and flow diverters contain significant amounts of metals, notably nickel, which can cause allergic reactions in a considerable portion of the population. These allergic responses may lead to complications like in-stent stenosis (ISS) and TIA/Stroke in patients receiving stents or flow diverters for intracranial aneurysms. We conducted a systematic review of studies from inception until July 2023, which reported outcomes of patients with metal allergy undergoing neurovascular stenting. The skin patch test was used to group patients into those with positive, negative, or absent patch test results but with a known history of metal allergy. Our review included seven studies with a total of 39 patients. Among them, 87% had a history of metal allergy before treatment. Most aneurysms (89%) were in the anterior circulation and the rest (11%) were in the posterior circulation. Skin patch tests were performed in 59% of patients, with 24% showing positive results and 33% negative. Incidental ISS was observed in 18% of patients, and the rate of TIA/Stroke was reported in 21%. The pooled rates of ISS and TIA/Stroke were higher in the first group (43% and 38%) compared to the second (18% and 9%) and third groups (15% and 15%), but these differences were not statistically significant. The current neurosurgical literature does not provide a conclusive association between metal allergy and increased complications among patients undergoing neurovascular stenting. Further studies are necessary to gain a more comprehensive understanding of this topic.

Overcoming False-Negative Patch Tests: A Systematic Literature Review.

Exogenous allergens, found in cosmetic products, jewelry items, antiseptics and antibacterials, plants, and solvents, can cause clinical allergic contact Dermatitis (ACD). To help identify and discern which allergen is causing ACD, clinicians use patch tests, but they can yield false-negative results at times. Examining potential reasoning for false negatives is particularly helpful when a patient's history and physical examination strongly suggest ACD, and the patch test is negative. A strong history and physical presentation suggestive of ACD warrants additional patch testing or other methods to verify a false-negative patch test result. We conducted a literature review to compile various reasonings and solutions for false-negative patch tests in suspected ACD patients. Utilizing EMBASE, Scopus, PubMed, and Google Scholars, 49 articles were included by using search terms such as "False negative patch test" or "False-negative patch test" and "allergic contact Dermatitis," or "ACD." Common factors that led to false-negative patch test results include low allergen concentration, inadequate percutaneous penetration, technique error, immunosuppressive therapy, and ultraviolet exposure. Potential solutions include using different vehicles, concentration, increasing reading time, repeating the patch test, intradermal testing, and repeat open application testing. If a false-negative patch test is suspected, then intradermal testing can be administered to ensure the specificity of the patch test result. Considering the main contributing factors and solutions to false-negative patch tests, clinicians can accurately diagnose ACD and administer proper treatment plans.

Solvent Induced Cumulative Insult Irritant Contact Dermatitis through Glove Permeation: A Case-Report on the Chronic Occupational Skin Lesion

A young female laboratory worker presented with chronic cumulative skin lesion over hands. The occupational exposure history supported the prolonged and frequent exposure to multiple solvents which are recognised as work irritants, improper work practice and wrong use of protective glove. The diagnosis of Irritant Contact Dermatitis (ICD) was supported by workplace dermatology risk factors, clinical features, negative skin patch test to rule out hypersensitivity reaction and fulfilment of all seven Mathias Criteria. The effective management of occupational contact dermatitis requires practices change and exposure control. The comprehensive Hand Care Programs must be individualised and incorporate several important elements namely the skin care screening and surveillance, early referral for Occupational Health assessment, effective education and training programs and provision of hand moisturising products. The support of return to work (RTW) among the affected workers is of paramount important in order to minimise the negative impacts on their quality of work as well as home life.

Pertuzumab and Trastuzumab Patch Testing In Acute Generalized Exanthematous Pustulosis (AGEP): A Case Report and Review of the Literature

We describe the use of pertuzumab and trastuzumab patch testing to determine the safety of rechallenging a patient with these medications after developing AGEP. The patient is a man in his 60s with HER2-amplified, RAS/RAF wild type and MMR-proficient metastatic sigmoid colon cancer, who developed facial erythema and oral ulceration two days after receiving treatment with atezolizumab infusion and pertuzumab/trastuzumab/hyaluronidase subcutaneous injection. By day six post-treatment, he developed diffuse erythematous papules coalescing into plaques on the trunk and extremities most prominent in a flexural distribution. Our patient had a negative patch test result for pertuzumab and trastuzumab, suggesting that the reaction was probably related to atezolizumab or hyaluronidase and ruling out pertuzumab and trastuzumab as causative agents.

Contact hypersensitivity to Indian standard patch test series correlates with disease severity among children with atopic dermatitis.

Background There is emerging evidence of a relationship between atopic dermatitis (AD) and allergic contact dermatitis (ACD), though the data available are scarce with conflicting viewpoints. We explored the occurrence of contact hypersensitivity among children with atopic dermatitis by patch testing them with the Indian standard series and tried to correlate the presence of contact hypersensitivity with the clinical severity of AD in these children. Methods In this single-centre, cross-sectional study, children between 6 months and 12 years diagnosed with atopic dermatitis were included and patch tested with the Indian standard series. Outcome parameters were the proportion of patients having positive patch-test reactions, the proportion of positive patch-test reactions for each allergen and factors associated with patch test positivity in atopic dermatitis. Results Of the 136 patients, 80 were boys. The mean age of the study population was 5.6 ± 3.2 years. Twenty-eight (20.6%) patients had patch test positivity at 96 h. Fragrance mix was the commonest allergen, followed by potassium dichromate, cobalt chloride hexahydrate and nickel. SCORing atopic dermatitis (SCORAD) was significantly higher in patients with positive patch tests as compared to patients with negative patch tests (P = 0.009). Conclusion Greater disease severity in atopic dermatitis was found to be associated with patch test positivity. Limitations Inability to establish relevance in about 50% of the patients was a limitation of our study. Follow-up data regarding the impact of allergen avoidance is not available.

CD07 Corticosteroids: a complex case of friend and foe

Abstract Hypersensitivity reactions to corticosteroids, either immediate or delayed, represent a clinical paradox as one would not expect such reactions to compounds with anti-inflammatory and immunomodulatory effects. We present the case of a 67-year-old patient referred to our service with three episodes of a delayed hypersensitivity reaction to steroids. The first episode occurred in 2016 when the patient was treated for a chest infection with amoxicillin and 5-mg prednisolone. Following 1 day of treatment, the patient developed a widespread erythematous rash. The patient remained systemically well, and the rash resolved over 3 weeks. Subsequently, the patient tolerated penicillin with no issues. In April 2019, following a bupivacaine and triamcinolone steroid injection to the shoulder and back for pain management, the patient developed a widespread erythematous rash. The patient denied any blistering or peeling of the skin and was systemically well. This rash took ∼3 weeks to settle. In August 2019, the patient had a dexamethasone injection to her back and subsequently developed a widespread erythematous pruritic rash. On this occasion, the patient reported symptoms of nausea and headache. The patient has avoided all steroids since 2019 and has developed no rashes. The patient had a negative skin prick test to bupivacaine under the care of immunology. Patch testing results showed positivity to 10/13 compounds tested in the corticosteroid series (Table 1). The patient had a negative patch test result to tixocortol-21-pivalate (0.1%) and to hydrocortisone-21-acetate (1%). In the fragrance series, the patient tested positive to one compound, Santalum album oil (sandalwood oil) 2%. Corticosteroids are classified into four groups (A, B, C and D), with the last subdivided into D1 and D2. A further classification proposed divides corticosteroids into three groups based on their structural characteristics. Allergic reactions to corticosteroids have been reported, with an estimated prevalence of 0.1–0.3%, with contact dermatitis to corticosteroids having a higher frequency (0.5–5%). Although not life-threatening, contact allergy to corticosteroids can have significant impacts on quality of life and on treatment.Table 1Corticosteroid series patch testing resultsHapten/compound%48 h96 hBudesonide0.01+/–+++Betamethasone-17-valerate1++Triamcinolone acetonide1++Tixocortol-21-pivalate0.1Alclometasone-17,21-dipropionate1+/–Clobetasol-17-propionate1++Dexamethasone-21-phosphate disodium salt1+Hydrocortisone-17-butyrate+/–+++Desoximetasone1+++Betamethasone-17,21-dipropionate1+++Methylprednisolone aceponate1+++Corticosteroid mix2.1++++Hydrocortisone-21-acetate1

Incidence and prevalence of occupational contact dermatitis in hairdressing apprentices: A 3-year prospective cohort study.

It is known that a large number of hairdressing apprentices (HA) develop occupational contact dermatitis (OCD) during schooling, but studies that address prevalence of contact sensitization in HAs with hand eczema are missing. To assess the prevalence, incidence rate and clinical characteristics of OCD, including contact sensitization, in a sample of Croatian HAs. A total of 408 HAs from 25 Croatian towns were examined at the beginning of education and monitored at the end of each school year. Clinical evaluation of skin changes was performed using the Osnabrueck Hand Eczema Severity Index (OHSI). Standard patch test (PT) with baseline and hairdresser series of contact allergens was performed in 46 HAs with skin changes lasting ≥3 months. The overall incidence rate of OCD was 32.3/100 person-years, and the 3-year prevalence 50.3%. Contact sensitization was found in 14 out of 46 (30.3%) HAs, with 10 of these 14 HAs (71.4%) sensitized to specific hairdressing allergens. The strongest reactions were found to PPD. HAs with positive PT had higher OHSI than HAs with negative patch test (median, IQR: 3, 2-4 vs. 2, 2-4). Contact sensitization to specific hairdressing chemicals was found in 71.4% of HAs with a positive patch test, supporting evidence on the early contact sensitization to occupational allergens among HAs.

Delayed Severe Gingivitis After Placement of Orthodontic Braces in an Atopic Teenager: A Case Report and Literature Review.

We report a case of a 15-year-old atopic patient presenting with delayed, severe ulcerative hypertrophic gingivitis after placement of orthodontic braces, which required removal of braces and restorative laser surgical procedures. Patch testing to multiple metals and chemicals showed weak positive reactions to steel bands and formaldehyde. The patient experienced urticarial, gingivitis, and other intraoral symptoms after patch testing and re-exposure to nickel-containing products. In contrast, nickel, cobalt, and cobalt-chromium (Co-Cr) bracket patch testing sites were negative. Nickel-caused contact dermatitis is Type IV delayed hypersensitivity reaction occurring at least 24 h after exposure. This reaction can result in intraoral blisters, ulcerations, eczematous and urticarial reactions of the face and more distant skin areas. This case illustrates the intraoral delayed response, symptom resolution after removing the braces, and brackets and local reactions upon subsequent nickel exposure, despite negative patch testing and lymphocyte stimulation test to nickel. This case further illustrates the difficulty associated with diagnosing nickel allergy.

EVALUATION AND MANAGEMENT OF DELAYED HYPERSENSITIVITY REACTION TO INSULIN IN

<h3>Introduction</h3> Type I hypersensitivity to insulin is rare. In most adverse reactions to insulin, additives, excipients, or preservatives are implicated, resulting in type III or IV hypersensitivity. We describe an adolescent patient with delayed type hypersensitivity to insulin and discuss evaluation and management strategies. <h3>Case Description</h3> A 16-year-old female with type I diabetes mellitus used an insulin pump without problems for 6 years. Recently, she began to develop a delayed, itchy, painful pump site rash. Symptoms were managed with pump site rotation, trials of various insulins, trials of return to manual insulin injections, and oral antihistamines. A variety of allergy testing—percutaneous, intradermal, and patch—has been largely negative, suggesting against type I and IV hypersensitivities. Punch biopsy of the rash was performed with basic pathology and various stains completed, consistent with type IV hypersensitivity. Table 1 shows test results. <h3>Discussion</h3> Type III hypersensitivity was the leading differential diagnosis given some delayed intradermal positive results, negative patch testing, and previous positive serum IgG to insulin; however, biopsied tissue did not show immune complex deposition. The pathology was more consistent with a type IV hypersensitivity. Little is known about effectively managing these delayed hypersensitivity reactions as insulin therapy continues. Our patient started adjunctive metformin therapy and will undergo additional, extensive patch testing with Dermatology. Other therapies to consider include low-dose corticosteroid co-infusion with insulin and/or biologic drug therapy. It is important to distinguish that these patients do not have insulin allergy but may require support from an allergist to facilitate comfortable receipt of chronic diabetes treatment.

Metal Allergy in Foot &amp; Ankle: A Systematic Review

Category: Basic Sciences/Biologics; Other Introduction/Purpose: Metal hypersensitivity is common in the general population, affecting between 10-15%. Many different metals are constituents of orthopaedic devices used for foot and ankle surgery; therefore, it is expected to influence patient outcomes. A variety of different reactions, both systemic and localized, have been reported, along with treatment strategies. However, there is no accepted protocol to evaluate, diagnose and manage patients with suspected metal hypersensitivity reactions. Current literature characterizing metal hypersensitivity in foot and ankle and guidance on management is lacking. Methods: A comprehensive literature search of Ovid MEDLINE and EMBASE was performed from inception to 23-Nov-2021 using MeSH search terms focusing on the foot and ankle, orthopaedic surgeries, a variety of metal types, and hypersensitivity reactions. A total of 43 studies were identified. All full-text, English, experimental and observational studies, reporting on metal hypersensitivity in the context of foot and/or ankle surgeries using metal-containing orthopaedic devices were included. Article screening, quality assessment, and data extraction was performed by two reviewers. Disagreements were resolved by discussion or the vote of a third reviewer. Results: A total of 45 patients (18 male and 27 female) were included from 15 papers. Mean age was 55.5 years. There were 42 static and three arthroplasty implants included. Metal hypersensitivity diagnosis was performed with specialist consults, and most commonly, patch testing (e.g. with standard array or implant components). Patch testing was most commonly positive to nickel (thirteen), followed by cobalt (four), vanadium (three), and other less commonly used metals. Mean follow up was 20.8 months. Fifteen patients (12 with a positive patch test, 1 with a negative patch test and two not tested), all symptomatically improved following metallic implant removal; four patients had implants removed for unclear reasons; one patient remained symptomatic despite implant removal but had a negative patch test. The remaining 25 patients retained their implants without significant symptoms regardless of patch test result. Conclusion: Metal hypersensitivity in the context of foot and ankle surgery is not widely reported. It should be considered as a differential diagnosis in patients who present with hypersensitivity-type symptoms with previous surgery with metallic implants, after infection and mechanical failure have been ruled out. Patch testing can be helpful in identifying these patients. Removal of static implants after fracture union in trauma cases typically resulted in symptom resolution. Metallic arthroplasty implant removal presents more of a clinical challenge. Future research should focus on creating a framework to identify at risk patients and diagnose foot and ankle patients with metal allergy.

Negative patch tests: what should we think about these results?

Negative patch tests: what should we think about these results?

Delayed cutaneous adverse drug reactions to sympathomimetics after oral intake of over-the-counter medications

Sympathomimetics are a therapeutic class of drugs wich aim is to mimic adrenaline and noradrenaline, contained in many over-the-counter medications such as “Humex Cold”. To date, 32 cases of delayed hypersensitivity induced by pseudoephedrine have been reported in the literature ranging from MPE to severe cutaneous adverse drug reactions, including 3 PEAG and 4 EMP. Cross-reactivities within sympathomimetics are not yet well established. We describe here two case reports of delayed cutaneous drug reactions to sympathomimetics, one maculo-papular exanthema and one acute generalized exanthematic pustulosis. We evaluated cross-reactivity and review the sympathomimetic drugs to be able to make a summary table. We first did patch tests with the molecule that caused the initial skin reaction. Then, searching for cross-reaction: we tested with patch tests thirteen sumpathomimetics with different properties. We also performed skin biopsies on positive patch tests for histological analysis in RNA later for the patient who presented acute generalized exanthematic pustulosis. Patient who did maculopapular exanthema had a negative patch test to pseudoephedrine after two series of allergological tests but did a recurrence of maculo-papular exanthema after oral provocation to pseudoephedrine and with an emergency treatment with ephedrine. A new allergological workup revealed a positive ephedrine patch test at 72 h. The search for cross-reactivity had highlighted during a 3rd exploration positive patch tests at 72 h for: ephedrine, pseudoephedrine in three different molecules (Humex, Actifed, Rhinadvil) anda positive patch test to phenylephrine. Patient who did an acute generalized exanthematic pustulosis had a positive pseudephedrine patch test. No cross-reactivity with other sympathomimetics was found. Literature is weak regarding cases of delayed cross-hypersensitivity to sympathomimetics even if searching for cross-allergies seems to be necessary. We propose summary table and a list of of sympathomimetic drug to test when faced to a delayed cutaneous drug reaction.

The relationship between atopy and allergic contact dermatitis in Israeli patients.

IntroductionWhether individuals with atopic diseases have a different risk of contact allergy compared to those who are non-atopic is controversial and data are conflicting.AimTo explore the association between atopy and allergic contact dermatitis (ACD).Material and methodsThis retrospective cross-sectional study included 301 patients referred to a tertiary clinic to evaluate ACD. Demographic details including personal and familial mucosal or cutaneous atopic status were recorded. Patch tests were tailored to their clinical presentations and relevant exposures.ResultsAt least 1 positive patch test reaction was observed in 177 patients (59% of the study cohort), of which 52% had a history of atopic diseases, compared with 44% of patients with a negative patch test result (p = 0.2). Additionally, 147 patients had an atopic background, of which 92 (62%) had ≥ 1 positive patch test result, compared with 55% of non-atopic patients (p = 0.2). Nickel sulphate was the most common contact allergen (13.4% of the patch test reactions).ConclusionsWe identified a positive tendency for atopic diseases among individuals with ACD and vice versa. Our study supports the aggregate data from previous studies despite the non-significant differences between the study and control groups. However, further research performed in larger populations of patients is necessary to evaluate the real association between atopy and ACD on a solid basis. Our results indicate the necessity of systematic patch testing in patient setups with atopic background and chronic dermatitis.

Patch Testing in Drug Eruptions: Practical Aspects and Literature Review of Eruptions and Culprit Drugs.

There is overwhelming evidence that many delayed cutaneous adverse drug reactions (beginning >6 hours after drug intake) are mediated by delayed-type (type IV) hypersensitivity, including maculopapular eruptions, erythroderma, symmetrical drug-related intertriginous and flexural exanthema/baboon syndrome, eczematous eruptions, fixed drug eruptions, acute generalized exanthematous pustulosis, and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome. Therefore, after resolution of the reaction, patch tests should be performed as first diagnostic method to identify the culprit drug(s). This article provides tools to perform drug patch tests properly and safely, discussing clinical history, indications, procedure, drug patch test materials, sensitivity, the meaning of negative patch tests, and safety of the procedure. In addition, a literature review of eruptions and culprit drugs is provided in tabular format.

Eczéma palpébral à la norfloxacine en collyre chez un enfant : intérêt du ROAT

Eyelid contact dermatitis to antibiotic eye drops is increasingly reported, but the fluoroquinolone is exceptionally involved. Patch tests are used to confirm the nature of the allergen, however, false-negative results are increasingly found. Alternative tests such as ROAT (Repeated Open Application Test) may be useful. We report the case of a 6 year old child with norfloxacin-induced palpebral eczema with negative patch tests, where the ROAT was of great interest.