The use of skin testing in the investigation of cutaneous adverse drug reactions

Eczematous drug eruption in patients with psoriasis under anti-interleukin-17A: does interleukin-22 play a key role?

BACKGROUND

Eczematous drug eruption (EDE) is a spongiotic skin reaction in response to systemic medications. To date, EDE has been described in patients treated with anti-interleukin (IL)-17A monoclonal antibodies with a prevalence of 2.2%-12.1%.

AIM

To describe the clinical and histological features and the skin cytokine milieu in patients with EDE induced by anti-IL-17A biologics.

METHODS

This was a prospective study, enrolling patients with psoriasis who developed EDE during treatment with two anti-IL-17 biologics, ixekizumab and secukinumab, from June 2019 to April 2021. Skin biopsies were taken from all patients: a 5-mm lesional biopsy (LB) and a 3-mm nonlesional biopsy (NLB). The LB sample was split into two parts, one for histological examination and the other for cytokine profile evaluation.

RESULTS

During the study period, treatment with an anti-IL-17A drug was given to 289 patients of whom 8 (2.8%) developed EDE during the treatment. Histopathological evaluation suggested a diagnosis of spongiotic dermatitis in all eight patients. Cytokine gene expression showed a predominance of T helper (Th)2/Th22 cytokines in EDE lesions with a large increase in IL-4, IL-22 and S100A7 levels in both LB and NLB samples compared with healthy skin. IL-4, IL-22 and S100A7 were significantly higher in LB compared with NLB samples. IL-26 levels were also significantly increased in both LB and NLB compared with healthy skin, whereas low levels of IL-23A were found in both LB and NLB.

CONCLUSION

Eczematous drug eruption skin lesions have mainly Th2/Th22 features, with IL-22 playing a major role in their pathogenesis. EDE seems to be the result of an imbalance towards a Th2/Th22 response, secondary to the blockade of IL-17A activity.

Results of patch testing in Acute generalized exanthematous pustulosis (AGEP): a literature review

The literature on positive patch test results in acute generalized exanthematous pustulosis (AGEP) is reviewed. 93 drugs were identified that have together caused 259 positive patch tests in 248 patients suffering from AGEP. The drug classes causing the highest number of reactions are beta-lactam antibiotics (25.9%), other antibiotics (20.8%), iodinated contrast media (7.3%) and corticosteroids (5.4%), together accounting for nearly 60% of all reactions. The highest number of reactions to individual drugs was to amoxicillin (n=36), followed by pristinamycin (n=25), diltiazem (n=14), amoxicillin-clavulanic acid (n=13), clindamycin (n=11) and iomeprol (n=8); 59 of the 93 drugs each caused a single case only. The "Top-10" drugs together caused over 50% of all reactions. The sensitivity of patch testing (percentage of positive reactions) in patients with AGEP is largely unknown, but may generally be around 50%, which also applies to pristinamycin. Patch testing in AGEP appears to be safe, although mild recurrence of AGEP skin symptoms or other rashes may occur occasionally. Clinical aspects of AGEP, including epidemiology, etiology and pathophysiology, clinical features, histology, treatment, and prognosis are briefly presented, as are diagnosing the disease and identifying the culprit drugs with patch tests, intradermal tests, in vitro tests, and challenge tests. This article is protected by copyright. All rights reserved.

The Role of Patch Testing in Evaluating Delayed Hypersensitivity Reactions to Medications

Confirming drug imputability is an important step in the management of cutaneous adverse drug reactions (CADR). Re-challenge is inconvenient and in many cases life threatening. We review the literature on ideal patch testing technique for specific CADRs. Testing should be performed approximately 3 months after the resolution of the eruption using standard patch testing techniques. Commercially available patch test preparations are available for a minority of drugs, so in most cases, testing should be performed with the drug at various recommended concentrations and in different vehicles. Testing to all known excipients, such as dyes, vehicles and preservatives is also important. Immunosuppressive medications should be discontinued or down titrated to the lowest tolerable dose to decrease the risk of false negative reactions. We provide an overview of expert recommendations and extant evidence on the utility of patch testing for identifying the culprit drug in common CADRs and for specific drug or drug classes. Overall, there appears to be significant variability in the patch test positivity of different drugs, which is likely the result of factors intrinsic to the drug such as dermal absorption (as a function of lipophilicity and molecular size) and whether the drug itself or a downstream metabolite is implicated in the immune reaction. Drugs with high patch test positivity rates include beta-lactam antibiotics, aromatic anticonvulsants, phenytoin, and corticosteroids, among others. Patch testing positivity varies both as a function of the drug and type of CADR. The sum of the evidence suggests that patch testing in the setting of morbilliform eruptions, fixed drug eruption, acute generalized exanthematous pustulosis, and possibly also drug-induced hypersensitivity syndrome, photoallergic and eczematous reactions may be worthwhile, although utility of testing may vary on the specific drug in question for the eruption. It appears to be of limited utility and is not recommended in the setting of other complex CADR, such as SJS/TEN and leukocytoclastic vasculitis.

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

ABSTRACT

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.

Patch tests in nonimmediate cutaneous adverse drug reactions: The importance of late readings on day 4

BACKGROUND

Patch tests (PTs) with two readings have been used for decades to identify the culprit drug in nonimmediate cutaneous adverse drug reactions (NICADRs), followed more recently by late reading of intradermal tests (IDTs). Some teams tend to perform PTs with only one reading before IDTs or even directly perform IDTs.

OBJECTIVES

To evaluate the relevance of a late PT reading on day 4 (D4) in NICADRs.

METHODS

We retrospectively selected patients who had a PT for an NICADR between July 2014 and March 2020.

RESULTS

During the study period, 328 patients had a PT with available results. Among the 75 positive-PT patients with available data for the two readings, 41 (54.7%) had positive results on D2 and D4 and 34 (45.3%) had negative results on D2 but positive results on D4. No patient had positive results on D2 and negative results on D4.

CONCLUSION

This study shows that a D4 reading enhanced the PT-positive results. A positive PT result allows for reducing the number of IDTs, which are more difficult and costly to perform. Our series suggests that a late PT reading at D4 should be performed for exploring NICADRs.

Skin Resident Memory T Cells May Play Critical Role in Delayed-Type Drug Hypersensitivity Reactions

Delayed-type drug hypersensitivity reactions (dtDHR) are immune-mediated reactions with skin and visceral manifestations ranging from mild to severe. Clinical care is negatively impacted by a limited understanding of disease pathogenesis. Though T cells are believed to orchestrate disease, the type of T cell and the location and mechanism of T cell activation remain unknown. Resident memory T cells (T_RM) are a unique T cell population potentially well situated to act as key mediators in disease pathogenesis, but significant obstacles to defining, identifying, and testing T_RM in dtDHR preclude definitive conclusions at this time. Deeper mechanistic interrogation to address these unanswered questions is necessary, as involvement of T_RM in disease has significant implications for prediction, diagnosis, and treatment of disease.

Eczematous Drug Eruptions

Eczematous drug eruptions are a heterogenous group of skin reactions that resemble eczema both clinically and histologically. We reviewed the literature and cataloged the systemically administered medications that cause these eruptions, along with their characteristic clinical presentations. We identified three primary pathophysiologic etiologies: (1) cutaneous immunomodulation, (2) skin dehydration, and (3) delayed hypersensitivity. Notably, eczematous eruptions caused by altered immunity in the skin may be increasing in incidence as some responsible drugs, in particular biologic therapies (such as tumor necrosis factor-α and interleukin-17 inhibitors) and targeted cancer treatments (including immune checkpoint inhibitors and epidermal growth factor receptor inhibitors), become more commonly employed in clinical practice. Other notable causes of eczematous eruptions include antiviral agents for hepatitis C virus and cardiovascular medications in elderly individuals, and notable subtypes of eczematous reactions include systemic contact dermatitis and photoallergic reactions, which are also discussed. The diagnostic gold standard is drug rechallenge and most reactions may be treated effectively with emollients, topical corticosteroids, and oral antihistamines.

Evaluation of drug patch tests in children

Background: Patch tests are used to diagnose nonimmediate T-cell-mediated drug hypersensitivity reactions. The aim of this study was to evaluate the results of patch tests performed with suspect drugs in children. Methods: Patients < 18 years of age who had a drug patch test at the pediatric allergy outpatient clinic of our hospital between January 2014 and January 2020 were included in the study. Age, sex, culprit drug(s), reaction characteristics, and patch test results were recorded from the patients' files. Results: A total of 105 drug patch tests were performed on 71 patients during the study period. The patients' median age was 7 years (interquartile range, 4-11 years), and 57.7% (n = 41) were boys. Twenty-three patients (32.3%) had severe cutaneous adverse reaction (Stevens-Johnson syndrome in 11, drug reaction with eosinophilia and systemic symptoms in 9, and acute generalized exanthematous pustulosis in 3 patients), 45 (63.3%) had maculopapular rashes, and 3 (4.2%) had fixed drug eruption. A total of 20 patch test results (28%) were positive: 18 of 44 patch tests (40.9%) with antiepileptic drugs and 2 of 48 patch tests (4.1%) with antibiotics. Positive results were obtained in 23% of the patch tests (6/26) in 20 patients with severe cutaneous adverse reactions and in 17.7% of the patch tests (14/79) in 51 patients with mild cutaneous reactions. No adverse reactions occurred during or after the patch tests. Conclusion: In our study, patch test positivity was more common with antiepileptic drugs and in patients with severe cutaneous drug reaction.

HLA-B*1502 is associated with aromatic anticonvulsant drug-induced cutaneous adverse drug reactions among the Hakka population in China

Background

The purpose of this study was to analyze the correlation between aromatic antiepileptic drug-induced cutaneous adverse drug reactions and HLA-B*1502 genotype in patients from the Hakka population in Meizhou.

Methods

A total of 214 epileptic patients taking aromatic (n = 94) or non-aromatic anticonvulsants (n = 120) were included in the study from September 2016 to May 2018. Clinical data for the patients were analyzed retrospectively and HLA-B*1502 genotype testing was carried out.

Results

Thirty patients were HLA-B*1502(+) (14.02%). The proportion of HLA-B*1502(−) genotype and incidence of adverse drug reactions (ADRs) differed significantly between the two drug groups. In the aromatic anticonvulsant group, maculopapular eruption (MPE), Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and hypersensitivity syndrome (HSS) occurred in 10 patients, including eight HLA-B*1502(+) and two HLA-B*1502(−) patients. MPE, HSS, SJS, and TEN occurred in 26 patients in the non-aromatic anticonvulsant group, including one HLA-B*1502(+) and 25 HLA-B*1502(−) patients. There was a significant correlation between the proportions of HLA-B*1502(+) genotype and induced cutaneous adverse drug reactions in the two groups.

Conclusions

HLA-B*1502 is associated with aromatic anticonvulsant drug-induced cutaneous adverse drug reactions among the Hakka population in Meizhou, China.

S3 guidelines: Epicutaneous patch testing with contact allergens and drugs - Short version, Part 1

Epicutaneous patch testing is the diagnostic standard for the detection of allergic contact dermatitis. The present guidelines are aimed at residents and board-certified physicians in the fields of dermatology and allergology as well as other medical specialties involved in establishing the indication for patch testing and its execution in patients with contact dermatitis and other forms of delayed-type hypersensitivity. The target audience also includes other health care providers and insurance funds. Based on a systematic literature search and a formal consensus process (S3), the guidelines were developed by dermatologists in collaboration with pediatricians, occupational medicine physicians, nursing staff as well as patient representatives. The systematic methodological approach and appraisal of evidence upon which the recommendations are based are outlined in a separate method report that also contains evidence tables. The guidelines address general aspects of patch testing as well as medicolegal issues. The recommendations given relate to topics such as the indication for patch testing, informed patient consent, as well as the choice of test substances, test chambers and test site, duration of exposure, reading times and interpretation of test reactions. Furthermore, recommendations are provided with respect to endogenous and exogenous factors, specific patient groups (children, pregnant women, immunosuppressed individuals) as well as possible risks and adverse events associated with patch testing using contact allergens. Note: This publication is part 1 of the short version of the S3 guidelines for "Epicutaneous patch testing using contact allergens and drugs" (registry no. 013 - 018; date: March 20, 2019; valid until December 31, 2021). Part 2 of the short version will be published in the next issue. The long version of these guidelines can be accessed at www.awmf.org. The method report is available as online publication (https://www.awmf.org/leitlinien/detail/ll/013-018.html) and contains the evidence tables in its appendix.

Intradermal Tests With Drugs: An Approach to Standardization

Background: Intradermal tests (IDTs) are performed and interpreted differently in drug allergy centers making valid comparison of results difficult.

Objective: To reduce method-related and intercenter variability of IDTs by the introduction of a standardized method.

Materials and methods: In 11 centers of the European Network for Drug Allergy, IDTs were prospectively performed with saline and with amoxicillin (20 mg/ml) using (1) the local method and (2) the standardized European Network in Drug Allergy (ENDA) method (0.02 ml). The diameters of the initial injection wheal (Wi) for the different volumes and sites injected obtained from each center were analyzed.

Results: The most reproducible method was to fill a syringe with test solution, then expel the excess fluid to obtain exactly 0.02 ml. The median Wi diameter with 0.02 ml injection using the standardized method was 5 mm [range 2–10 mm; interquartile range (IQR) 5–5 mm; n = 1,096] for saline and 5 mm (range 2–9 mm; IQR = 4.5–5 mm; n = 240) for amoxicillin. IDT injection sites did not affect the Wi diameter. Training improved precision and reduced the variability of Wi diameters.

Conclusion: Using the standardized IDT method described in this multicenter study helped to reduce variability, enabling more reliable comparison of results between individuals and centers.

[Sebotropic drug eruption after ingestion of bee pollen]

INTRODUCTION

The medical literature contains five cases of exanthema with sebaceous tropism induced by consumption of kava-kava extract filed under the name of sebotropic drug reaction. Herein we report a new case following consumption of bee pollen.

PATIENTS AND METHODS

A 37-year-old man consulted for erythemato-papular and fixed plaques of the face, upper trunk and shoulders present for 3 days. Standard blood tests were normal except for neutrophil leukocytosis at 9.8 G/l and eosinophilia at 1.4 G/l. Cutaneous biopsy of a facial plaque revealed folliculocentric lesions with necrosis of sebocytes in the sebaceous gland, associated with an eosinophil-rich infiltrate. The patient had begun consuming bee-pollen granules 3 weeks before the onset of symptoms. The rash regressed within 3 weeks of cessation of pollen consumption. Patch tests (ICDRG battery, propolis 1% Vaseline dilution and bee pollen provided by the patient, both pure and in a 30% dilution in Vaseline) were negative at 48 and 72h.

DISCUSSION

The clinical-pathological correlation was consistent with a diagnosis of sebotropic drug reaction induced by the consumption of bee pollen. The diagnosis was based on papular exanthema of the seborrheic zones occurring 2 to 3 weeks after initial intake of the offending substance, with histological evidence of inflammatory necrosis of the sebaceous glands.

CONCLUSION

We report what is to our knowledge the first case of sebotropic drug reaction following ingestion of bee pollen.

A case of entecavir-associated bullous fixed drug eruption and a review of literature

Fixed drug eruption (FDE) is a type of drug reaction characterized by localized erythema, hyperpigmentation, and bullous at the same site(s), generally observed following every intake of a causative drug. Delayed-type cellular hypersensitivity (Type IVC) is considered to play a role in FDE etiology. Several antibiotics, barbiturates, oral contraceptives, nonsteroidal anti-inflammatory drugs, laxative-containing phenolphthalein, metronidazole, and quinine are known to be the primary drugs responsible for FDE. Bullous FDE, on the other hand, is a relatively rare form of FDE. Hepatitis B is a significant worldwide health problem, and entecavir is a common nucleoside (deoxyguanosine) analog used for treating hepatitis B; however, it has various side effects, such as lactic acidosis, myalgia, azotemia, hypophosphatemia, headache, diarrhea, pancreatitis, and neuropathy, and, in rare cases, cutaneous drug eruption. Our aim is to present a case of entecavir-associated bullous drug reaction, which has not been reported in the literature. Furthermore, we performed a review of literature to compile previously reported entecavir-associated drug reactions.

Aetiopathogenesis of severe cutaneous adverse reactions (SCARs) in children: A 9-year experience in a tertiary care paediatric hospital setting

BACKGROUND

Severe cutaneous adverse reactions (SCARs) are delayed-type hypersensitivity reactions to drugs including as follows: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), Stevens-Johnson syndrome (SJS), Toxic Epidermal Necrolysis (TEN) and Acute Generalized Exanthematous Pustulosis (AGEP). Incidence, triggers and management of SCARs have not been investigated in large-scale epidemiological studies on children.

OBJECTIVE

The aim of our study was to collect epidemiological, clinical and aetiological data from children with SCARs referred to our tertiary care paediatric hospital of Florence.

METHODS

From 2010 to 2018 charts of children with diagnosis of SCAR were reviewed, and data collected during the acute phase and/or the subsequent allergy evaluation. Patients underwent patch tests, intradermal tests and lymphocyte transformation tests. All children were investigated for infectious diseases.

RESULTS

Incidence of SCARs in hospitalized children was 0.32% over a 9-year period. Fifty-four children were enrolled (31 M; 23 F; median age 6.5 years): 17 cases of DRESS, 30 SJS, 3 TEN, 2 AGEP, 1 linear immunoglobulin A bullous disease (LABD) and 1 pemphigus. Twenty-eight out of 54 patients underwent drug allergy investigations, and 50% of them resulted positive. Combining clinical history and results of allergy work-up, 74% SCARs seem to be caused by drugs, 18.6% by both drugs and infections, 3.7% by infections, and 3.7% remained idiopathic. No deaths occurred.

CONCLUSIONS

In this study, SCARs incidence is in line with literature data. Drugs were most commonly the leading cause. Management of SCARs requires cooperation among professional figures for an early diagnosis and a prompt treatment. Mortality rate seems to be lower in children.

Macrolide Allergic Reactions

Macrolides are antimicrobial agents that can be used to treat a variety of infections. Allergic reactions to macrolides occur infrequently but can include minor to severe cutaneous reactions as well as systemic life-threatening reactions such as anaphylaxis. Most reports of allergic reactions occurred in patients without prior exposure to a macrolide. Cross-reactivity among macrolides may occur due to the similarities in their chemical structures; however, some published literature indicates that some patients can tolerate a different macrolide. Most published reports detailed an allergic reaction to erythromycin. Desensitization protocols to clarithromycin and azithromycin have been described in the literature. The purpose of this article is to summarize macrolide-associated allergic reactions reported in published literature. An extensive literature search was conducted to identify publications linking macrolides to hypersensitivity reactions.

Fixed drug eruption due To 2,3-dimercapto-1-propanesulfonic acid (DMPS) treatment for mercury poisoning: a rare adverse effect

BACKGROUND

Fixed drug eruptions (FDE) are characterized by recurrent, usually solitary erythematous or dark red macular, plaque or bullous lesions, all at the same site. Among the first choices for antidotal treatment in mercury exposure, 2,3-dimercapto-1-propanesulfonic acid (DMPS) is generally a drug with a low incidence of side effects. FDE due to DMPS was not detected in our literature research and so we aimed to present this rare case.

CASE REPORT

Forty-eight-year-old male patient, gunpowder and explosives factory worker, was admitted to our hospital because of mercury exposure and we started DMPS treatment. On the second day of chelation treatment, swelling and felting on lips and complaints of wound formation in genital areas started. Annular, purple color plaque on penis with no angioedema was observed. Case was regarded as FDE. Systemic and topical steroid therapy was started after termination of chelation therapy and lesions regressed with steroids.

DISCUSSION

Drug eruptions are substantially common dermatological problems and can be seen in about 2.2% of inpatients. The most common unexpected effects of DMPS are allergic skin reactions. The clinical state regress rapidly after the cessation of chelation therapy.

Drug Reaction with Eosinophilia and Systemic Symptoms (DReSS): How Far Have We Come?

Drug reaction with eosinophilia and systemic symptoms (DReSS), also known as drug-induced hypersensitivity syndrome (DiHS), is an uncommon severe adverse reaction to medications. It is important to recognize it as it is potentially fatal and can cause significant morbidity. From the first reports of drug reactions related to certain anticonvulsants characterized by fever, liver enzyme elevation, and skin changes, our continuously growing understanding of this entity has allowed us to describe its physiopathology and clinical features even further. The relationship of genetic factors, viral activation, and specific drug exposure is now known to play a role in this disease. There is still not a widely accepted marker for DReSS/DiHS, but the spectrum of clinical and laboratory features has now been better outlined. The mainstay of treatment is the use of systemic corticosteroids, but other options such as intravenous immunoglobulin, cyclosporine, mycophenolate mofetil, rituximab, and cyclophosphamide have been described. We present a comprehensive review of the literature on DReSS/DiHS, focusing on its history, etiopathogenesis, diagnosis, therapeutic approach, and outcome.

Non-immediate-reading skin tests and prolonged challenges in non-immediate hypersensitivity to beta-lactams in children

BACKGROUND

A minority of children reporting non-immediate reactions to beta-lactams (BLs) are allergic. Allergy workup usually includes late-reading (48-72 hours) skin tests (ST) and short (1-3 days) drug provocation tests (DPT), regardless of the chronology of the index reaction. The sensitivity of hyper-late-reading (≥6-7 days) ST and of prolonged DPT for the diagnosis of non-immediate hypersensitivity to BLs is yet to be determined.

OBJECTIVES

To establish the diagnostic values of late-reading ST and hyper-late-reading ST and of prolonged DPT in children reporting non-immediate reactions to BLs.

METHODS

Prospective assessment of children reporting non-immediate reactions to BLs with late- and additional hyper-late-reading intradermal (ID) and patch tests, and if negative, with prolonged DPT.

RESULTS

Five hundred and fifty children reporting reactions to a single or several BLs (674 suspected BLs) were included. Non-immediate hypersensitivity to BLs was diagnosed in 63 children (11.5%), reporting 66 reactions (9.8%), based on responses in ST (n = 17, 25.8%: 5 to ID, 8 to patch tests, and 4 to both tests), DPT (n = 43, 65.2%), and clinical history (n = 6, 9.1%), including 3/9 children with severe cutaneous adverse reactions. Skin test positivity was observed after the 6-7th day in 14/17 children, and DPT positivity after a median time of 3 days. No severe reaction was observed after ST or during prolonged DPT.

CONCLUSION

Additional hyper-late-reading of ST enhanced their positivity. However, their overall sensitivity remained weak, especially in non-severe cases. Prolonged DPT are safe and may improve the performance of DPT in the diagnosis of non-immediate hypersensitivity to BLs.

[Hypersensitivity reactions to beta-lactam antibiotics]

Allergy to beta-lactam antibiotics is a common condition and about 10% of patients report being allergic to penicillin. However, this diagnosis is largely overestimated. Two types of allergy should be distinguished and include immediate hypersensitivity that can lead to anaphylactic shock and delayed hypersensitivity, ranging from the most common maculopapular exanthema to severe bullous toxidermia or life-threatening DRESS. Allergy challenge with oriented skin tests according to the clinical features, supplemented with oral challenge in the absence of contraindication, will confirm or invalidate the diagnosis of beta-lactam allergy and will help to identify if necessary safe alternatives to beta-lactams.

Patch testing in non-immediate cutaneous adverse drug reactions: value of extemporaneous patch tests

BACKGROUND

Patch testing following a standardized protocol is reliable for identifying the culprit drug in cutaneous adverse drug reactions (CADRs). However, these patch tests (PTs) require pharmaceutical material and staff, which are not always easily available.

OBJECTIVES

To evaluate an extemporaneous PT method in CADRs.

METHODS

We retrospectively analysed data for all patients referred to our department between March 2009 and June 2013 for patch testing after a non-immediate CADR. The patients who supplied their own suspected drugs were tested both with extemporaneous PTs and with conventional PTs. Extemporaneous PTs involved a nurse crushing and diluting the drug in pet. in a ratio of approximately one-third to two-thirds. Standardized PTs were performed according to guidelines, with commercial drugs diluted to 30% or with active ingredients diluted to 10%. We analysed the data for the two PT methods in terms of the number of positive test reactions, drugs tested, and type of CADR for patients in whom the two PT methods were used.

RESULTS

In total, 75 of 156 patients underwent the two PT procedures, including 91 double tests. Overall, 21 tests gave positive reactions with the two methods, and 69 other tests gave negative results with the two methods.

CONCLUSION

Our series yielded results similar to those of published series concerning the types of CADR and the drugs responsible. Our results suggest that, for CADRs, if a patient supplies a suspected drug but if the pharmaceutical material and staff are not available for conventional PTs, extemporaneous PTs performed by the nurse with the commercial drug used by the patient can be useful and reliable.

Risk and safety requirements for diagnostic and therapeutic procedures in allergology: World Allergy Organization Statement

One of the major concerns in the practice of allergy is related to the safety of procedures for the diagnosis and treatment of allergic disease. Management (diagnosis and treatment) of hypersensitivity disorders involves often intentional exposure to potentially allergenic substances (during skin testing), deliberate induction in the office of allergic symptoms to offending compounds (provocation tests) or intentional application of potentially dangerous substances (allergy vaccine) to sensitized patients. These situations may be associated with a significant risk of unwanted, excessive or even dangerous reactions, which in many instances cannot be completely avoided. However, adverse reactions can be minimized or even avoided if a physician is fully aware of potential risk and is prepared to appropriately handle the situation. Information on the risk of diagnostic and therapeutic procedures in allergic diseases has been accumulated in the medical literature for decades; however, except for allergen specific immunotherapy, it has never been presented in a systematic fashion. Up to now no single document addressed the risk of the most commonly used medical procedures in the allergy office nor attempted to present general requirements necessary to assure the safety of these procedures. Following review of available literature a group of allergy experts within the World Allergy Organization (WAO), representing various continents and areas of allergy expertise, presents this report on risk associated with diagnostic and therapeutic procedures in allergology and proposes a consensus on safety requirements for performing procedures in allergy offices. Optimal safety measures including appropriate location, type and required time of supervision, availability of safety equipment, access to specialized emergency services, etc. for various procedures have been recommended. This document should be useful for allergists with already established practices and experience as well as to other specialists taking care of patients with allergies.

Patch testing - a valuable tool for investigating non-immediate cutaneous adverse drug reactions to antibiotics

BACKGROUND

Antibiotics are among the most frequent causes of cutaneous adverse drug reactions (CADR); patch testing may be an important tool in their evaluation and management. We assessed the role of patch testing as a diagnostic tool in non-immediate CADR to antibiotics, and evaluated cross-reactivity among them.

METHODS

We reviewed data from all patients with non-immediate CADR attributed to antibiotics, which were patch tested between 2000 and 2014 at our dermatology department.

RESULTS

Patch tests were performed in 260 patients, and showed overall reactivity to antibiotics of 21.5%, especially in the context of drug reactions with eosinophilia and systemic symptoms (DRESS) (31.6%), maculopapular exanthema (MPE) (21.8%), Stevens-Johnson syndrome/toxic epidermal necrolysis (20%) and acute generalized exanthematous pustulosis (AGEP) (18.1%). Patch test reactivity was higher for amoxicillin, mainly in DRESS (44.4%) and MPE (25.6%), and dicloxacillin (50% in AGEP and 37.5% in MPE). Reactivity to clindamycin occurred, especially in the setting of MPE (23.2%). In AGEP and DRESS, patch tests were useful in detecting reactivity to quinolones (50-100%). Overall reactivity was lower for vancomycin (9.1%), co-trimoxazole (8.6%), macrolides (4.8%) and cephalosporins (4.4%). Positive patch tests for more than one antibiotic occurred in 29/56 cases (51.8%), mostly explained by cross-reactions. Twenty of 24 cases reacted to both amoxicillin and ampicillin. All five cases reacting to ciprofloxacin cross-reacted with other quinolones.

CONCLUSION

Although oral rechallenge is considered the gold standard for confirming drug imputability in CADR, patch testing could be suggested as a first choice in the study of non-immediate reactions, since it is a safe and valuable procedure.

Cutaneous adverse drug reactions in the elderly

PURPOSE OF REVIEW

Population ageing is a worldwide phenomenon. The presence of multiple comorbidities, polypharmacy, age-related changes in pharmacokinetics and pharmacodynamics, as well as skin changes in the elderly contribute to a unique diagnostic and management problem. This article reviews the epidemiology of cutaneous adverse drug reactions in the elderly and elaborates on a few specific types of reactions which are more relevant to the elderly.

RECENT FINDINGS

Chronic dermatoses, for example, eczema, have been reported to be associated with the use of long-term medications such as calcium channel blockers and hydrochlorothiazide. Elderly patients receiving treatment for cancers may develop chemotherapy-related cutaneous side effects, including those associated with newer 'targeted' molecular therapies. Elderly patients who develop severe cutaneous adverse drug reactions, such as Stevens-Johnson syndrome and toxic epidermal necrolysis, have worse prognosis in terms of mortality.

SUMMARY

Persons of advanced age often have multiple comorbidities and are on multiple medications. This can result in higher probability of an elderly person developing drug eruptions. It is important for the clinician to be aware of the range of drug-related eruptions and their implications.

Contact dermatitis: a practice parameter-update 2015

This parameter was developed by the Joint Task Force on Practice Parameters, which represents the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma & Immunology. The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Contact Dermatitis: A Practice Parameter-Update 2015." This is a complete and comprehensive document at the current time. The medical environment is changing and not all recommendations will be appropriate or applicable to all patients. Because this document incorporated the efforts of many participants, no single individual, including members serving on the Joint Task Force, are authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information or interpretation of this practice parameter by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma & Immunology. These parameters are not designed for use by the pharmaceutical industry in drug development or promotion. Previously published practice parameters of the Joint Task Force on Practice Parameters for Allergy & Immunology are available at http://www.JCAAI.org or http://www.allergyparameters.org.

Diagnostic evaluation and risk factors for drug allergies in children: from clinical history to skin and challenge tests

BACKGROUND

Parent or self-reported drug allergy claims frequently overestimate the real incidence of hypersensitivity reactions. A detailed and algorithmic diagnostic evaluation of drug reactions may allow a proper diagnosis.

OBJECTIVE

The aim of this study was to determine the confirmation rates and risk factors for confirmed allergic drug reactions in children.

SETTING

Mersin University Hospital in Turkey.

METHOD

The study consisted of children between ages of 8 months and 18 years with the history of suspected drug allergy as reported by the clinician or the patients. Parents were interviewed by a clinician to complete questionnaires that included questions about demographic data and characteristics of index drug reaction. Immediate reactions (IRs) were assessed with immediate-reading skin prick (SPT) and intradermal tests (IDT). Nonimmediate reactions (NIRs) were assessed with SPT, both early and delayed reading of IDT and patch tests. In case of negative skin tests, drug provocation tests were performed. The possible risk factors for confirmed drug allergy in univariate analysis (p < 0.1) were entered into the multivariate logistic regression analysis to determine independent predictors.

MAIN OUTCOME MEASURE

(1) Confirmation rates of drug allergy (2) Risk factors related to confirmed drug allergy in children.

RESULTS

We evaluated a total of 180 suspected drug allergy reactions in 97 children, mainly to antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs) and anticonvulsants. Among all suspected allergic drug reactions, 97 (53.9 %) were immediate type and 83 (46.1 %) were non-immediate type. The average time interval between the reaction and allergologic work-up was 5 months. Drug allergy confirmation rates were 30.1 % for beta-lactams, 27.2 % for non-betalactams, 21.1 % for NSAIDs and 30 % for anticonvulsants. Eight of 54 confirmed NIRs showed positivity on immediate skin tests. Regulatory T cells, TGF-β and IL-10 levels were not different between groups with and without confirmed drug allergy. A strong family and personal history of drug allergy were found to be significantly related to the confirmed allergic drug reactions.

CONCLUSION

Parent or self-reported drug allergy should be evaluated with a standardized diagnostic work-up before strict prohibitions are made. In addition, family and personal histories of drug allergy were significant risk factors related to allergic drug reactions in children.

Cellular in vitro diagnosis of adverse drug reactions

Adverse drug reactions can manifest clinically in a variety of ways. Whilst the majority can be explained by dose-dependent side effects, there is group of unpredictable immunological or non-immunological intolerances that represent a particular diagnostic challenge. Skin tests are frequently negative, whilst challenge tests are time-consuming and often hazardous. Against this backdrop, cellular in vitro tests play a particularly important role in the identification of the causative drug. Whilst basophil tests can be used in the case of immunoglobulin E (IgE)- as well as non-IgE-mediated hypersensitivity reactions, T-cellular test methods assist in the diagnosis of drug eruptions. The reliability of individual tests can be affected by a variety of parameters, such as the pathomechanism underlying the drug reaction, the causative medication, or the point in time of testing. Not only is a sound knowledge of the basic principles of the individual assays an essential prerequisite for correctly indicating and interpreting this test method, but also an awareness of these additional factors.

Intradermal Tests for Diagnosis of Drug Allergy are not Affected by a Topical Anesthetic Patch

The use of topical anesthesia to perform intradermal tests (IDTs) for drug allergy diagnosis was never investigated. We aimed to determine the effects of a topical anesthetic patch containing prilocaine-lidocaine on wheal size of IDT with drugs. Patients who had positive IDT as part of their investigation process of suspected drug hypersensitivity were selected. IDT were performed according to guidelines. Anesthetic patch (AP) was placed and the same prior positive IDT, as well as positive histamine skin prick test (SPT) and negative (saline IDT) controls, were performed in the anesthetized area. Patients with negative IDT were also included to check for false positives with AP. Increase in wheals after 20 minutes both with and without AP was recorded and compared. 45 IDT were performed (36 patients), of which 37 have been previously positive (14 antibiotics, 10 general anesthetics, 6 non-steroidal anti-inflammatory drugs, 3 iodinated contrasts, 3 anti-Hi-histamines and 1 ranitidine). Mean histamine SPT size without the AP was 4.7 mm [95%CI (4.4-5.1]), and 4.6 mm [95%CI(4.2-5.0)] with anesthesia. Mean wheal increase in IDT for drugs without the anesthesia was 4.5 mm [95%CI(3.3-5.7)] and with anesthesia was 4.3 mm [95%CI(2.8-5.8)]. No statistical significant differences were observed between skin tests with or without AP for histamine SPT (P=0.089), IDT with saline (P=0.750), and IDT with drugs (P=0.995). None of the patients with negative IDT showed positivity with the AP, or vice-versa. The use of an AP containing prilocaine-lidocaine does not interfere with IDT to diagnose drug allergy, and no false positive tests were found.

International Consensus on drug allergy

When drug reactions resembling allergy occur, they are called drug hypersensitivity reactions (DHRs) before showing the evidence of either drug-specific antibodies or T cells. DHRs may be allergic or nonallergic in nature, with drug allergies being immunologically mediated DHRs. These reactions are typically unpredictable. They can be life-threatening, may require or prolong hospitalization, and may necessitate changes in subsequent therapy. Both underdiagnosis (due to under-reporting) and overdiagnosis (due to an overuse of the term ‘allergy’) are common. A definitive diagnosis of such reactions is required in order to institute adequate treatment options and proper preventive measures. Misclassification based solely on the DHR history without further testing may affect treatment options, result in adverse consequences, and lead to the use of more-expensive or less-effective drugs, in contrast to patients who had undergone a complete drug allergy workup. Several guidelines and/or consensus documents on general or specific drug class-induced DHRs are available to support the medical decision process. The use of standardized systematic approaches for the diagnosis and management of DHRs carries the potential to improve outcomes and should thus be disseminated and implemented. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), formed by the European Academy of Allergy and Clinical Immunology (EAACI), the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), and the World Allergy Organization (WAO), has decided to issue an International CONsensus (ICON) on drug allergy. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences and deficiencies of evidence, thus providing a comprehensive reference document for the diagnosis and management of DHRs.

[Allergies to antibiotic drugs: their importance in otorhinolaryngology]

BACKGROUND

In 2009, over 40 million prescriptions for antibiotic drugs were counted in outpatient medical care in Germany. This represents a turnover of more than 750 million euros. With over 80 million daily defined doses (DDD), amoxicillin was the most frequently prescribed antibiotic in Germany in 2008. Given the average of 5775 DDD per doctor, otolaryngologists prescribed more antibiotics than specialists in any other field of medicine in 2008; approximately 82% of these were β-lactams and tetracyclines.

MATERIAL AND METHODS

This article is based on selective literature-based research using the PubMed database. The keywords used in the search were:"allergy","anaphylaxis" and"hypersensitivity", in combination with "penicillin","cephalosporin","carbapenem","cotrimoxazole","macrolide","aztreonam" and"tetracycline".

RESULTS

Allergic reactions to antibiotics are among the most frequently reported adverse side effects arising from drug treatment. However, non-allergic adverse side effects owing to drug intolerance are also very common and may be clinically indistinguishable from allergic reactions. Owing to a frequent lack of appropriate diagnostic investigation, the decision to withhold effective standard treatments from patients is often based solely upon anamnestic observations. Up to 10% of respondents in an unselected population report an allergy to penicillin. In 80% of these cases, however, no penicillin-specific IgE-antibodies can be detected.

CONCLUSION

A detailed understanding of the symptoms, diagnostic options and possible cross reactions pertaining to allergic reactions to antibiotics, as well to non-allergic adverse side effects with similar clinical appearance, is very important for otolaryngologists. This profound knowledge ensures that the correct diagnostic steps are taken and that appropriate treatment decisions prevent the unnecessary use of reserve antibiotics.