Frequency and diagnostic findings of type I and type IV reactions to beta-lactam antibiotics - significance of the time interval between clinical reaction and skin testing.

BACKGROUND: The prevalence of allergies to beta-lactam antibiotics is significantly overestimated based on anamnestic data - with significant medical and economic consequences. The aim of the study was to determine the frequency of immediate and delayed type reactions to beta-lactam antibiotics in order to optimize diagnostics and therapy. One focus was on the time interval between reaction and testing. PATIENTS AND METHODOLOGY: Anamnestic and diagnostic data of patients with suspected allergy to beta-lactam antibiotics who were examined in our department between 2020 and 2022 were analyzed. RESULTS: 27/116 (23%) patients reacted in the skin tests. Type I sensitizations were detected in 4/35 patients (11%), type IV sensitizations in 23/83 (28%). In the case of negative in vitro diagnostics and skin testing, inpatient provocation tests were performed in 41/89 (46%). Type I allergies were confirmed in two of the 13 provoked patients (15%) with immediate type reactions, type IV allergies in three of 29 (10%) with delayed type reactions. The results were clearly related to the time interval after reaction. At less than one year, 19% (22/116) reacted, whereas only 4% (5/116) reacted at more than one year (for type I reaction 9% vs. 3%; for type IV reaction 23% vs. 5%).  CONCLUSIONS: The importance of the time interval between clinical event and allergological testing supports the guideline recommendation for skin testing within one year. Guideline recommendations on the diagnostic procedure for unclear reactions that occurred in the more distant past are desirable in order to rule out allergies to beta-lactam antibiotics.

Delayed hypersensitivity reactions to iodinated contrast media: A diagnostic approach by skin tests.

BACKGROUND: Adverse drug reactions to iodinated contrast media (ICM) have risen due to their increasing use in x-ray-based imaging modalities. Delayed hypersensitivity reactions are mainly caused by nonionic monomeric compounds and represent an issue impacting the diagnostic-therapeutic pathways of cancer, cardiology and surgery patients. OBJECTIVES: To prospectively evaluate the usefulness of skin tests in delayed hypersensitivity reactions to ICM and to evaluate the tolerability of iobitridol, a monomeric nonionic low osmolality compound, as a possible safe alternative. METHODS: Patients with delayed hypersensitivity reactions to ICM referred to us from 2020 to 2022 were prospectively enrolled in the study. All patients underwent patch test and, if negative, intradermal test with the culprit ICM and iobitridol as alternative. RESULTS: A total of 37 patients (females 24, 64.9%) were enrolled in the study. Iodixanol and iomeprol were the most frequently involved ICM (48.5% and 35.2%, respectively); 62.2% of patients presented maculopapular eruption, while 37.8% reported delayed urticaria-like rash. Skin tests resulted positive to the culprit ICM in 19 patients (51.4%), 16 to patch test and 3 to intradermal test. Skin tests with iobitridol, tested as alternative, resulted positive in 3/19 patients (15.8%). All 16 patients with negative results to iobitridol were administered this ICM and tolerated it. CONCLUSIONS: In at least half of patients, delayed-type hypersensitivity was demonstrated by skin tests, particularly by patch test. This diagnostic approach resulted simple, cost-effective and safe, not only to confirm the culprit ICM but also to identify iobitridol as feasible alternative.

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.

Delayed allergic skin reactions to vaccines.

Background: Recent advances in vaccination against the severe acute respiratory syndrome coronavirus 2 pandemic have brought allergists and dermatologists to the forefront because both immediate and delayed hypersensitivity reactions have been reported. Objective: This literature review focused on delayed reactions to vaccines, including possible causative agents and practical information on how to diagnose, evaluate with patch testing, and manage subsequent dose administration. Methods: Currently published reviews and case reports in PubMed, along with data on vaccines from the Centers for Disease Control and Prevention web site. Relevant case reports and reviews that focused on delayed reactions to vaccines were selected. Results: Most delayed hypersensitivity reactions to vaccines include cutaneous manifestations, which vary from local persistent pruritic nodules to systemic rashes. The onset is usually within a few days but can be delayed by weeks. Multiple excipients have been identified that have been implicated in delayed vaccine reactions, including thimerosal, formaldehyde, aluminum, antibiotics, and gelatin. Treatment with antihistamines, topical corticosteroids, or systemic corticosteroids alleviates symptoms in most patients. Such reactions are generally not contraindications to future vaccination. However, for more-severe reactions, patch testing for causative agents can be used to aid in diagnosis and approach further vaccination. Conclusion: Delayed-type hypersensitivity reactions to vaccines are not uncommon. If needed, patch testing can be used to confirm agents, including antibiotics, formaldehyde, thimerosal, and aluminum. In most cases, delayed cutaneous reactions are not contraindications to further vaccine administration.

Diagnosis of non-immediate hypersensitivity to amoxicillin in children by skin test and drug provocation tests: A retrospective case-series study.

BACKGROUND: Skin rash often occurs upon oral administration of amoxicillin in children, due to non-immediate hypersensitivity. However, information on delayed hypersensitivity to amoxicillin is scarce. Moreover, the appropriate diagnostic method and actual diagnostic rate of delayed hypersensitivity to amoxicillin among Japanese children are unclear. We conducted intradermal tests (IDTs) and drug provocation tests (DPTs) and retrospectively investigated the proportion of children with a definitive diagnosis of non-immediate hypersensitivity to amoxicillin. We then evaluated the characteristics of patients with a positive allergic workup. METHODS: We enrolled children referred for suspected findings of mild or moderate non-immediate hypersensitivity to amoxicillin between August 2018 and March 2020. If the IDT in the delayed phase was negative, DPT with amoxicillin (60-90 mg/kg/day) was performed for 7 days. Non-immediate hypersensitivity to amoxicillin was defined when IDT or DPT was positive. We evaluated the potential of the drug-induced lymphocyte stimulation test (DLST) to reveal hypersensitivity to amoxicillin. RESULTS: This study enrolled 27 children. Fourteen children (52%) had hypersensitivity to amoxicillin, of whom 12 had positive IDTs and two had positive DPTs. No differences in age, sex, history of allergic disease, days from oral use to symptom onset, type of rash at symptom onset, generalized rash, and DLST results were observed between the hypersensitivity and non-hypersensitivity groups. CONCLUSIONS: Examination should be performed for children with mild or moderate reactions because positive cases have no significant features and half of the suspected cases are negative.

Intradermal Testing Identifies 1 in 4 Patients with Nonimmediate Penicillin Allergy.

BACKGROUND: Intradermal testing with delayed reading (IDTdr), used routinely in many centers, may identify delayed reactions to penicillins. However, few studies have compared the results of IDTdr with drug provocation test (DPT). The aim of this study was to examine the proportion of provocation-positive patients testing positive on IDTdr. METHODS: Fifty-seven patients with a positive DPT occurring >2 h after intake of penicillin V, dicloxacillin, pivampicillin, or amoxicillin had an IDTdr with penicillin G, amoxicillin, ampicillin, and dicloxacillin. A control group included 18 patients with negative DPTs with the suspected penicillin. RESULTS: In total 25% (n = 14) of provocation-positive patients tested positive on IDTdr. Among patients with positive IDTdr, 9/14 (64%) versus 11/43 (26%) in the IDTdr negative group (p < 0.05) had required oral steroids to treat skin reactions following DPT. No other differences between IDTdr positive and negative groups were found. No controls had a positive IDTdr. CONCLUSION: Investigating with IDTdr would have identified 25% of patients with a DPT-verified allergy with delayed reactions. It is difficult to target subgroups who will test positive on IDTdr. There were more patients who tested positive on IDT who had received oral steroids after DPT, and this may be an indication that skin reaction severity plays a role in skin testing diagnostics. Further potential predictors for positivity of IDTdr, such as duration of skin symptoms, should be assessed in large studies in order to optimize the investigations of nonimmediate drug allergic reactions.

Delayed hypersensitivity to antiepileptic drugs in children.

BACKGROUND: Antiepileptic drugs (AEDs) are widely used for the treatment of epilepsy, but they can be associated with the development of mainly delayed/non-immediate hypersensitivity reactions (HRs). Although these reactions are usually cutaneous, self-limited, and spontaneously resolve within days after drug discontinuation, sometime HR reactions to AEDs can be severe and life-threatening. AIM: This paper seeks to show examples on practical management of AED HRs in children starting from a review of what it is already known in literature. RESULTS: Risk factors include age, history of previous AEDs reactions, viral infections, concomitant medications, and genetic factors. The diagnostic workup consists of in vivo (intradermal testing and patch testing) and in vitro tests [serological investigation to exclude the role of viral infection, lymphocyte transformation test (LTT), cytokine detection in ELISpot assays, and granulysin (Grl) in flow cytometry. Treatment is based on a prompt drug discontinuation and mainly on the use of glucocorticoids. CONCLUSION: Dealing with AED HRs is challenging. The primary goal in the diagnosis and management of HRs to AEDs should be trying to accurately identify the causal trigger and simultaneously identify a safe and effective alternative anticonvulsant. There is therefore an ongoing need to improve our knowledge of HS reactions due to AED medications and in particular to improve our diagnostic capabilities.

Delayed corticosteroid hypersensitivity: a clinical management proposal.

Summary: Background. Different clinical pictures are related to corticosteroids (CS) non immediate hypersensitivity and the frequency of these reactions can be underestimated. The classification of CS in 3 groups and the identification of two patient's profiles has been proposed by Baeck to help clinicians in the management of these cases. Methods. Data of 14 patients with clinical history of delayed reactions to various CS and positive skin test and/or oral challenge are retrospectively analyzed. Results. Three different patterns of patients are identified evaluating history, clinical picture and tests results. The first one (6 pts, 43%) is characterized by cutaneous and/or mucosal reaction due to inhaled Budesonide and patch test positive only to topical molecules belonging to the group 1 of CS. The second pattern (4 pts) has clinical history of local and systemic skin reactions to the topic and parenteral administration of the same or other steroid drugs. Patients belonging to the third pattern (4 pts) have a history of systemic reactions to general administration of CS without previous contact reaction. Pattern 2 and 3 show a wide sensitization to molecules belonging to the 3 groups of CS. All the patients show patch test positive to Budesonide. Conclusions. Although the lack of standardization, the allergy workup proves useful to differentiate patients sensitized to one or few molecules from polysensitized and to identify the culprit drugs. Intradermal and challenge test are necessary to complete the diagnostic workup. The results suggest the possibility of a different management of patients. Patients of pattern one can be only patch tested with a limited series of CS belonging to the 3 groups. They don't need an extensive exclusion of steroids use. The pattern 2 and 3 must be submitted instead to a complete allergological individual evaluation to identify alternative tolerated drugs, because of the risk of systemic reactions. The Baeck's classification shows limited usefulness in these cases.

Trunnionosis and metal wear causing metal hypersensitivity: 2 sides of the same coin?

Metal hypersensitivity (MHS) and trunnionosis are being looked at more frequently. Both entities pose a difficult concern for surgeons and patients alike. This commentary highlights the similarities and differences between the 2 conditions. When a surgeon suspects either MHS or trunnionosis, both should be considered in the differential diagnosis. Both conditions are rare and should be considered a diagnosis of exclusion. The commentary proposes an outline on how to diagnose and treat the 2 entities.

Higher Prevalence of Nickel and Palladium Hypersensitivity in Patients with Ulcerative Colitis.

BACKGROUND: The etiology of ulcerative colitis (UC) remains elusive even though many genetic and environmental pathogenic factors have been reported. Aberrant inflammatory responses mediated by specific subsets of T cells have been observed in ulcerative lesions of UC patients. OBJECTIVES: To elucidate the involvement of a delayed-type hypersensitivity reaction in UC, we focused on dental metal hypersensitivity, a T cell-mediated, delayed-type allergic reaction that causes oral contact mucositis and systemic cutaneous inflammation. METHOD: We recruited 65 Japanese UC patients and 22 healthy controls (HC) and used the in vitro lymphocyte stimulation test to quantify their sensitivity to zinc, gold, nickel, and palladium - the metals that have been widely used in dentistry. All subjects were users of metallic dental implants and/or prostheses containing zinc, gold, nickel, and/or palladium as major constituents. RESULTS: Sixty percent of the UC patients were hypersensitive to at least one metal species, whereas 32% of the HC were hypersensitive to only a single metal species. The overall incidence of metal hypersensitivity was significantly higher for UC patients than for HC. Furthermore, a significantly greater proportion of UC patients were hypersensitive to nickel or palladium. The severity of the sensitivity to nickel and palladium was also significantly greater for UC patients than for HC. CONCLUSIONS: This pilot study demonstrates that UC patients have a significantly higher incidence of hypersensitivity to nickel and palladium, suggesting the possible involvement of dental metal hypersensitivity in UC pathogenesis.

Delayed Hypersensitivity Reactions Caused by Drug Excipients: A Literature Review.

The European Medicines Agency (EMA) defines excipients as the constituents of a pharmaceutical form apart from the active substance. Delayed hypersensitivity reactions (DHRs) caused by excipients contained in the formulation of medications have been described. However, there are no data on the prevalence of DHRs due to drug excipients. Clinical manifestations of allergy to excipients can range from skin disorders to life-threatening systemic reactions. The aim of this study was to perform a literature review on allergy to pharmaceutical excipients and to record the DHRs described with various types of medications, specifically due to the excipients contained in their formulations. The cases reported were sorted alphabetically by type of medication and excipient, in order to obtain a list of the excipients most frequently involved for each type of medication.

Treating COVID-19: Review of Drug Hypersensitivity Reactions.

The disease caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ie, coronavirus disease 2019 (COVID-19), has become a global pandemic since it was first reported in Wuhan, China in December 2019. Its severe clinical manifestations, which often necessitate admission to intensive care units, and high mortality rate represent a therapeutic challenge for the medical community. To date, no drugs have been approved for its treatment, and various therapeutic options are being assayed to address the pathophysiological processes underlying the clinical manifestations experienced by patients. New and old drugs administered as monotherapy or in combination to immunologically compromised patients may favor the development of adverse drug reactions, including drug hypersensitivity reactions, which must be identified and managed accordingly. Given the lack of herd immunity and the high rate of viral contagion, new cases are expected to emerge in the coming months. Thus, the probability of more adverse reactions or even new clinical manifestations may increase in parallel. Allergists must receive updated information on these treatments, as well as on the management of possible drug hypersensitivity reactions.

Increase in concentration of patch test allergen reduces patch test occlusion time to 12 hours without affecting patch test reactivity in patients with parthenium dermatitis.

BACKGROUND: Patch testing is the standard method to diagnose contact allergy. Patches are applied for 48 hours, which is inconvenient to patients in tropical weather. Therefore, we evaluated different patch test occlusion times with increased concentrations of an allergen to determine if occlusion time can be reduced without compromising patch test reactivity. METHODS: Patch test positive patients with parthenium dermatitis were enrolled and patch tested using five different concentrations (10%, 4%, 2%, 1%, and 0.5%) of parthenium extract. The patches were applied in triplicate. The first set was removed after 12 hours, whereas the second and third sets were removed after 24 and 48 hours, respectively. Readings were performed at 24, 48, and 96 hours. RESULTS: Fifty patients with parthenium dermatitis were included. The positive patch test reaction rates were comparable in all three sets at 24- and 48-hour readings irrespective of the occlusion time. All were positive, with 10%, 4%, and 2% concentrations at 96-hour reading with an occlusion time of 12 hours. CONCLUSION: An occlusion time of 12 hours seems adequate to elicit positive patch test reaction at a 96-hour reading if the concentration of patch test allergen can be increased, that is, from 1% to 2% in these patients.

Pediatric lichen planus pigmentosus possibly triggered by mercury dental amalgams.

Lichen planus pigmentosus is uncommon in childhood and its treatment is often challenging. We report a case of cutaneous lichen planus pigmentosus in a 10-year-old boy, without oral mucosal involvement, two months after an amalgam dental restoration. The diagnosis was based on the histopathological examination of a skin biopsy, the positive patch test to mercury, and the improvement after amalgam removal. Our case report suggests that metal allergy may play a role, and amalgam replacement may be followed by clinical improvement.

Two case reports of delayed-allergic reactions to clindamycin confirmed with a positive lymphocyte transformation test.

Summary: Clindamycin is widely used in the prophylaxis and treatment of infections due to its broad spectrum of antimicrobial activity. Hypersensitivity to clindamycin seems to be not very common (less than 1% of drug-allergic reactions) and it mostly appears as delayed T-cell mediated. For the diagnosis, skin testing is considered to be highly sensitive and rather safe, but cutaneous and systemic reactions have been described. Provocation test is considered the gold standard. However, it includes the possibility of severe reactions. We reported two cases of delayed allergic reaction to clindamycin, confirmed with a positive lymphocyte transformation test, showing this in vitro test like a promising diagnostic method because of its usefulness and safety.

A Systematic Review of the Literature of Delayed Inflammatory Reactions After Hyaluronic Acid Filler Injection to Estimate the Incidence of Delayed Type Hypersensitivity Reaction.

BACKGROUND: Hyaluronic acid (HA) dermal filler injection is believed to be a safe procedure. However, with the increase in the number of performed procedures and indications, the number of product-related complications, especially delayed inflammatory reactions, has also increased. Delayed-type hypersensitivity (DTH) reaction is one of these delayed inflammatory reactions, which is preventable by performing a pretreatment skin test. OBJECTIVES: The authors sought to find the incidence of delayed inflammatory reactions and DTH reaction after HA injection and to determine whether a pretreatment skin test is worthwhile to be performed. METHODS: The authors conducted a systematic literature review of all the relevant prospective studies, retrospective studies, and case reports on delayed inflammatory reactions and DTH reaction after HA filler injection. RESULTS: The incidence of delayed inflammatory reactions calculated from the prospective studies was 1.1% per year, and that of possible DTH reaction was 0.06% per year. Most retrospective studies estimated a percentage of delayed inflammatory reactions of less than 1% in 1 to 5.5 years. The incidence of DTH reaction would be lower than that. Among all the DTH cases reported, only about 5% of them were proven to be genuine DTH reactions. CONCLUSIONS: The incidence of both delayed inflammatory reactions and DTH reaction is low. There is evidence that genuine DTH reactions caused by HA fillers approved by the Food and Drug Administration do exist. This adverse event can be prevented by performing a pretreatment skin test. However, the incidence of DTH reaction is so low that the pretreatment skin test is not mandatory if Food and Drug Administration-approved HA fillers are used.

Sabra dermatitis: combined features of delayed hypersensitivity and foreign body reaction to implanted glochidia.

A striking dermatitis referred to by its colloquial designation of sabra dermatitis is associated with glochidia inoculation from the Opuntia cactus commonly known as the prickly pear. We report a 45-year-old woman who had an unexpected encounter with a cactus plant during a trip to Texas. She brushed up against the plant and was aware that she had been inoculated with several spines of the plant. Five days later she developed erythematous papules on the digits accompanied by swelling. The biopsy showed a very striking granulomatous reaction pattern within the dermis. There was a linear pattern of necrobiosis, likely representing a tract of inoculation injury palisaded by histiocytes including multinucleated forms. This necrobiotic tract demonstrated retained glochidia, each measuring roughly 40 to 70 microns in diameter. The nature of the inflammatory response is one that combines features of classic delayed hypersensitivity and an innate foreign body response. The glochidia are capable of eliciting a T cell mediated immune response; it is reasonable to assume that a Th1 cytokine signal is responsible for the unique pattern of inflammation including the secondary influx of neutrophils and relative lack of tissue eosinophilia.

Quantitative, Absolute Count-Based T-Cell Analysis of CD69 Upregulation as a New Methodology for In Vitro Diagnosis of Delayed-Type Hypersensitivity Reaction to Nickel.

BACKGROUND: T cells play a major role in delayed-type hypersensitivity reactions. Their reactivity can be assessed by measuring the upregulation of the activation marker CD69, followed by assessment of proliferation and cytokine production. The aim of our study was to develop a novel, whole blood-based, quantitative, absolute count activation index (AI) for analysis of CD69 upregulation in various subsets of T cells in nickel-hypersensitive patients and compare it with previously reported approaches. METHODS: The study population comprised 10 patients with nickel allergy and 9 healthy controls. CD69 expression of CD3+, CD3+CD4+, and CD3+CD8+ T cells in heparinized blood was determined with flow cytometry after incubation with nickel sulfate for 48 hours. The absolute count of CD69+ cells was determined using microbeads. Production of the cytokines IL-2, IL-5, IL-13, and IFN-γ was determined after stimulation of peripheral blood mononuclear cells with nickel sulfate for 48 hours. RESULTS: We showed absolute AI to be the most sensitive approach. The index was calculated as the ratio of the absolute count of nickel-stimulated CD69-positive T cells to the absolute count of CD69-positive T cells in nonstimulated blood. This novel quantitative approach was more discriminative than previously reported approaches in which the T-cell CD69 percentage AI and cytokine production are measured. CONCLUSIONS: Our results demonstrated that measuring the absolute CD69 AI is a novel and accurate approach for quantification of antigen-specific T cells in the blood of patients with hypersensitivity reactions to nickel. This approach may be useful for better in vitro assessment of patients with delayed-type hypersensitivity reactions.