Skin Patch Testing Research Articles

Managing paediatric eosinophilic gastroenteropathies: a community experience

Awareness and diagnoses of eosinophilic gastroenteropathies have increased over the past decade. We report 3 cases of eosinophilic gastroenteropathies in children who were diagnosed by endoscopy, allergy tested by skin prick and patch testing, and managed with the use of avoidance/elemental diets.

Érythème cutané provoqué par une neurostimulation cordonale postérieure : deux observations

Cutaneous complications following implantation of an electric system have been reported mainly after the implantation of pacemakers, cardiac defibrillators and morphine pumps. However, cutaneous complications following implantation of spinal cord stimulators are rarely described in the literature. Here we report two cases of cutaneous eruption at the spinal cord stimulation site, one involving foreign-body reaction to silicone in the neurostimulator electrodes or connector block and the other comprising contact dermatitis to silicone.Case 1: A 43-year-old woman had been implanted with a spinal cord stimulator. Four months after implantation, burning sensation and cutaneous inflammatory erythema were observed in the dorsolumbar region, with reduced efficiency of stimulation. Removal of the neurostimulator led to resolution of the cutaneous symptoms. Histopathological examination of the biopsy sample showed foreign-body granuloma formation. The same symptoms subsequently recurred on the surgical scar and histopathology showed granuloma formation in response to particles of silicone present in the connector. The cutaneous eruption subsided rapidly after excision. Case 2: In a 60-year-old man implanted with a spinal cord stimulator, pruriginous reticular erythema was rapidly observed on the skin just above the neurostimulator, with papules around the erythema. Histopathology of two cutaneous biopsies showed evidence of contact dermatitis. Skin-patch tests performed with components of the neurostimulator leads proved positive to two types of silicone after 72 hours. The eruption was successfully controlled using topical corticosteroid therapy.Reports of cutaneous eruptions after spinal cord stimulation are extremely rare. Here we report two different cutaneous reactions with two different pathophysiological mechanisms, both involving silicone. The first case is original because it is the first documented case of a foreign-body reaction involving granuloma formation in response to particles of silicone present in the components of a neurostimulator. The second case concerns contact dermatitis to silicone (present in the connector block and electrode sheaths).

Acute Kidney Injury Caused by Zonisamide-Induced Hypersensitivity Syndrome

Drug rash with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS), is a severe adverse drug reaction affecting multiple organs caused by drug treatment. The current report describes a man who was prescribed zonisamide for epilepsy and subsequently developed widespread skin rash, acute kidney injury, high-grade fever, eosinophilia, liver dysfunction, lymphadenopathy and an increase in antihuman herpesvirus-6 immunoglobulin G titer. Hypersensitivity to zonisamide was confirmed by the skin patch test. Based on these findings, the patient was diagnosed with DRESS/DIHS caused by zonisamide. This is the first report of acute kidney injury due to zonisamide-induced DRESS/DIHS.

Gold-coated pacemaker implantation after allergic reactions to pacemaker compounds

An 86-year-old man underwent pacemaker implantation for symptomatic atrio-ventricular block grade 2 Mobitz II. The patient suffered repeated admissions for iterative sterile wound necrosis, leading to two generator re-implantations. No bacterial infection was detected in the microbiological screening tests. The skin patch testing to titanium was negative. Nevertheless, we decided to remove the pacemaker system and to implant a gold-plated generator with polyurethane leads. Since then, there has been no recurrence of wound complications. Gold-plated generator and polyurethane leads are effective in treating allergic reactions to pacemaker system components in selected cases. Negative skin patch testing to titanium does not exclude allergic reaction to this pacemaker component.

The diagnostic value of atopy patch testing and prick testing in atopic dermatitis: facts and controversies

We conducted a systematic Medline search of the literature (1998-2008) on the criteria for performing the skin prick test and atopy patch testing (APT) to determine their utility in atopic dermatitis (AD). The skin prick, scratch, and skin patch tests are performed to identify which allergen is causing eczematous skin symptoms in patients with AD, or sneezing, nasal congestion, itchy eyes, wheezing, skin rash, and swelling. Many allergens in foods, drugs, and environmental substances (eg, ragweed and fungus), as well as contact allergens, can elicit eczematous skin reactions after epicutaneous application. Because no gold standard exists for aeroallergen provocation in AD, the APT is currently used to evaluate allergen without comparison with another accurate and reliable method. The APT is presumed to reflect delayed-phase clinical reactions. Even with delayed onset of symptoms (more than 2 hours after food ingestion), APT findings were not consistent among AD children. The APT could be used in children with gastrointestinal reactions to foods as well as AD. After standardization, the APT may provide further diagnostic information in addition to the skin prick test and serum immunoglobulin E values and may be able to evaluate the actual clinical relevance of immunoglobulin E-mediated sensitizations for eczematous lesions. The European APT model used with standardization of allergen concentration and vehicle may provide an important diagnostic tool to select patients for avoidance and for procedures of allergen-specific immunotherapy, but the clinical relevance of positive APT reactions awaits standardized provocation and avoidance testing.

Herpes Simplex and Eosinophilic Oesophagitis: The Chicken or the Egg?

Herpes Simplex and Eosinophilic Oesophagitis: The Chicken or the Egg?

Sensitization, asthma and allergic disease in young soccer players

The aim of this study was to identify the prevalence of allergic disease in young soccer players compared to age-matched students and to evaluate if this prevalence changes as the intensity of training increases. A modified ECRHS questionnaire was administered to 194 soccer players divided by age as Beginners (8-11 years), Juniors (12-16 years) and Under 21 (17-20 years) to evaluate the prevalence of allergic diseases and symptoms as well as drug consumption. Subjects with a positive personal history of allergic diseases underwent skin prick and/or patch tests. Age-matched students (n = 136) were used as a control group. The prevalence of allergic diseases was 34.5% in soccer players and 31.6% in control subjects (n.s.). Skin sensitization to inhalant allergens was detected in 14.4% of symptomatic soccer players and in 19.2% of control students (n.s.). Patch tests were positive in 35.7% of soccer players and 23.0% of controls with allergic dermatitis (n.s.). The prevalence of allergic diseases did not significantly change in relation to the intensity of training. Although the relative prevalence of sensitization to perennial allergens and asthma was less frequent in soccer players than in controls, and the occurrence of exercise-induced bronchoconstriction was similar in the two groups, soccer players used twice as many anti-allergic and anti-asthmatic drugs as control students. An increasingly intensive training programme is not associated with greater risk of allergic disease in soccer players. Therapy regimens of allergic athletes and exercisers should be monitored more closely to guarantee adequate treatment yet avoid inappropriate drug use and doping practices.

Successful Translation of Pharmacogenetics into the Clinic

Abacavir hypersensitivity syndrome (AHS) is a potentially life-threatening illness occurring in 4-8% of those initiating the drug. Early studies identified a strong association between the MHC class I allele HLA-B*5701 and AHS. These studies suggested that HLA-B*5701 holds promise as a screening test to prevent AHS, but concern arose from HLA-B*5701-negative cases with a clinical diagnosis of AHS, and particularly from early reports of apparently low sensitivities of HLA-B*5701 for AHS in patients of non-White race. However, open screening studies suggested that HLA-B*5701 screening can largely eliminate AHS. Furthermore, skin-patch testing was used in later-generation studies to separate those patients with true immunologically mediated AHS from those with false-positive clinical diagnoses. Currently, high-level evidence suggests that HLA-B*5701 has a negative predictive value of 100% for patch-test-confirmed AHS, which is generalizable across White and Black populations. Current HIV treatment guidelines have been revised to reflect the recommendation that HLA-B*5701 screening be incorporated into routine care for patients who may require abacavir. New laboratory techniques such as PCR and flow cytometric methods, as well as an international quality assurance program, have evolved to ensure the availability of cost-effective screening methods whose consistency and standard can be maintained over time. An elegant body of basic science has evolved, which supports and complements the clinical research in suggesting that AHS is specifically and exquisitely restricted by HLA-B*5701 and mediated by CD8+ lymphocytes. Abrogating factors explaining why 45% of those carrying HLA-B*5701 can tolerate abacavir remain to be defined. The research approach applied to AHS has led to a genetic screening test being successfully implemented globally in primary HIV clinical practice. The abacavir 'example' can be applied to other drugs to facilitate the development and operationalization of genetic tests that may be useful to predict and prevent otherwise unpredictable drug reactions.

Significance of dietotherapy on the clinical course of atopic dermatitis

The aim of this study was to determine the efficiency of individual balanced replacement diet in treatment of children with atopic dermatitis, to compare the course of atopic dermatitis and gastrointestinal disorders, as well as the data of skin patch test after a one-year period of dietary treatment. The study group included 154 children (their age varied from 6 months to 18 years) with atopic dermatitis, for whom food allergens were determined by allergic skin tests (skin prick and patch). These children were recommended an individual balanced replacement diet, where possible food allergens were replaced by other products that do not cause allergic reactions. After a one-year dietary treatment, 109 (70.8%) children (such number came for the second study) were tested repeatedly. The following aspects were evaluated for all these children: clinical course of atopic dermatitis (children's mothers provided answers about exacerbation of allergic rash during the last 12 months, gastrointestinal disorders, and used medicines), severity of the progress of atopic dermatitis (SCORAD index). Besides, skin patch test with 25 food allergens was carried out. Children who followed dietary recommendations were younger than children who failed to follow dietary recommendations because of a variety of reasons (P=0.01). Even 49 (62.8%) patients who followed dietary recommendations have shown the following results during the second test: allergic rash disappeared and they did not have to take medicines against allergy anymore. Patients who followed their individual dietary recommendations more rarely suffered from severe allergic rash problems during a 12-month period (P=0.01) and they had to take fewer medicines against allergy, compared to children who did not follow their dietary recommendations (P=0.001). Clinical course of atopic dermatitis in children who followed individual dietary recommendations was easier compared to children who did not follow such recommendations (P=0.001). During a one-year dietary treatment, 28.2% of children with atopic dermatitis became more tolerant to earlier food allergens. After the comparison of skin patch test results (before dietary treatment and after a one-year period), it was determined that only skin patch tests against buckwheat, oat, beef, and cacao did not change statistically significantly. Results of skin patch tests against other food products were found to be positive more rarely. Besides, children who followed their dietary recommendations suffered from gastrointestinal disorders more rarely as compared to children who did not follow their dietary recommendations (P=0.01). They suffered less from abdominal pain (P=0.01), abdominal distention (P=0.044), and constipation (P=0.035). Individual balanced replacement diet for children with atopic dermatitis helped to fully control nutrition of sick children from various age groups and had a positive effect on the clinical course of atopic dermatitis. Patients who followed their individual dietary recommendations suffered from severe allergic rash more rarely and they had to take fewer medicines against allergy as compared to children who did not follow dietary recommendations. Clinical course of atopic dermatitis in children who followed individual dietary recommendations was easier as compared to children who did not follow such recommendations. One-third of children with atopic dermatitis became more tolerant to earlier food allergens during a one-year period. After a one-year dietotherapy treatment, positive patch test reactions to many food products appeared to be more rarely, except for buckwheat, oat, beef, and cacao. Besides, children who followed their dietary recommendations suffered from gastrointestinal disorders (abdominal pain, abdominal distention, and constipation) significantly more rarely as compared to children who did not follow their dietary recommendations.

Skin testing in patients with hypersensitivity reactions to iodinated contrast media – a European multicenter study

Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions. The aim of this prospective study was to determine the specificity and sensitivity of skin tests in patients who have experienced such reactions. Skin prick, intradermal and patch tests with a series of contrast media were conducted in 220 patients with either immediate or nonimmediate reaction. Positive skin tests were defined according to internationally accepted guidelines. Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls. Skin test specificity was 96-100%. For tests conducted within the time period from 2 to 6 months after the reaction, up to 50% of immediate reactors and up to 47% of nonimmediate reactors were skin test positive. For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors. Contrast medium cross-reactivity was more common in the nonimmediate than in the immediate group. Interestingly, 49% of immediate and 52% of nonimmediate symptoms occurred in previously unexposed patients. Many of these patients were skin test positive, indicating that they were already sensitized at the time of first contrast medium exposure. These data suggest that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism. Skin testing appears to be a useful tool for diagnosis of contrast medium allergy and may play an important role in selection of a safe product in previous reactors.

Patch Testing for the Diagnosis of Anticonvulsant Hypersensitivity Syndrome

Anticonvulsant hypersensitivity syndrome (AHS), also known by the other names drug rash (reaction) with eosinophilia and systemic symptoms (DRESS) and drug-induced hypersensitivity syndrome (DIHS), is a rare and potentially fatal reaction that occurs in susceptible patients after exposure to certain drugs, including aromatic anticonvulsants. Because of its ill-defined clinical picture and resemblance to other diseases, the diagnosis of AHS is often difficult and requires a safe and reliable diagnostic test. The skin patch test has been proven to be very useful for prediction and diagnosis of some types of hypersensitivity reactions such as delayed drug eruptions to beta-lactam antibacterials. However, the diagnostic value of patch testing for AHS is yet to be determined and its negative predictive values (NPVs) and positive predictive values (PPVs) are still unknown. This systematic review attempts to evaluate the usefulness of patch tests in the diagnosis of AHS and to examine different technical aspects of patch testing that may contribute to its performance. We included studies in which aromatic anticonvulsant drugs are the likely causes of the hypersensitivity reaction. Analysis of original publications from 1950 to August 2008 and cited in PubMed, MEDLINE and EMBASE has revealed contradictory findings, possibly due mainly to the use of unstandardized methods. Numerous factors have been suggested to affect the final result of the test, including the following: type of drug tested; concentration of drug and vehicle used; timing of the test after exposure; and the clinical picture of the reaction. The PPV of the test in optimal conditions was as high as 80-90% depending on the drug tested. On the other hand, this value is around 10-20% in many other published studies. Although patch testing may be a useful diagnostic test for AHS, accurate determination of its sensitivity and specificity is yet to be achievable due to the lack of a gold standard test against which the performance of patch testing can be measured. Its PPV appears to be higher than its NPV, a matter that necessitates the use of other confirmatory tests in case of negative patch tests (e.g. careful systemic rechallenge). The benefit of testing appears to be maximal with certain drugs (i.e. carbamazepine and phenytoin) and for specific clinical manifestations (strong reactions). It should be performed 2-6 months after recovery from the date of the ADR for best results, with adequate vehicle control.

Irritant vocal cord dysfunction and occupational bronchial asthma: differential diagnosis in a health care worker

Vocal cord dysfunction (VCD) is an uncommon respiratory disease characterized by the paradoxical adduction of vocal cords during inspiration, that may mimic bronchial asthma. The pathogenesis of VCD has not been clearly defined but it is possible to recognize non-psychologic and psychologic causes. The majority of patients are female but, interestingly, a high incidence of VCD has been documented in health care workers. A misdiagnosis with asthma leads to hospitalisation, unnecessary use of systemic steroids with related adverse effects, and sometimes tracheostomy and intubation. In a subset of VCD patients, the disease can be attributed to occupational or environmental exposure to inhaled irritants. We report the case of a 45-year-old woman, working as a nurse, who complained of wheezing, cough, dyspnoea related to inhalation of irritating agents (isopropylic alcohol, formaldehyde, peracetic acid). She underwent chest radiography, pulmonary function assessment both in the presence and in the absence of symptoms, bronchial provocation with methacholine and bronchodilation test with salbutamol to recognize asthma's features, allergy evaluation by skin prick tests and patch tests and video-laryngoscopy. VCD diagnosis was made on the basis of video-laryngoscopy, that visualized the paradoxical motion of the vocal cords during symptoms, in the absence of other pathologic processes. This case fulfils the proposed criteria for the diagnosis of irritant VCD (IVCD). This is the first report of VCD onset following exposure to several irritants: formaldehyde, glutaraldehyde, sopropylic alcohol, peracetic acid-hydrogen peroxide mixture. These substances are used as cleaning and antiseptic agents in healthcare settings and some ones can also be found in many indoor environments. A correct diagnosis is important both to give the appropriate treatment and for medical legal implications.

Metal allergic reaction in chronic refractory in-stent restenosis

This study examined the relationship between chronic refractory (CR) in-stent restenosis (ISR) and metal allergic reaction. Although drug-eluting stent reduced the restenotic event compared with bare-metal stent, the mechanism of neointimal proliferation is not clear yet; however, bare-metal stent still remains as one of the choices. Of 128 bare-metal stent implanted patients who experienced target lesion revascularization at least once, 60 patients with the second ISR (study group) and 68 patients without the second ISR (control group) were compared in terms of result from the skin patch test for metal allergic reaction. Nickel was dominant among components of 316L stainless steel. The nickel-positive was observed in 19% (24/128) of all patients. Of 24 nickel-positive, 18 (30%) was in the study group, whereas 6 (9%) was in the control group (P=.02). According to multivariate analysis, the most significant predictor for CR-ISR was reference vessel diameter (P=.0010) followed by nickel-positive (P=.0033) and hyperlipidemia (P=.0305). The nickel-positive showed the highest odds ratio of 5.41 adjusted with confounder variables. This study with the second ISR showed that nickel was a major factor for CR-ISR. Further improvement of biocompatible material is required for coronary stents and strut-coating materials even in the drug-eluting stent era.

Drug-induced hypersensitivity syndrome: Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome induced by aspirin treatment of Kawasaki disease

Drug-induced hypersensitivity syndrome (DIHS), also known as drug reaction with eosinophilia and systemic symptoms (DRESS), is a severe multiple-organ condition caused by drug treatment. The current report describes a Japanese boy who underwent aspirin treatment for Kawasaki disease, and who subsequently presented with the manifestations of DIHS/DRESS syndrome. He had been treated with a single high dose of intravenous immunoglobulin and aspirin orally for Kawasaki disease. One month after the onset of Kawasaki disease, he developed a generalized maculopapular eruption, high-grade fever, leukocytosis with eosinophilia, and an increased number of atypical lymphocytes, severe liver dysfunction, lymphadenopathy, and prominent increases in antihuman herpesvirus-6 immunoglobulin G titer. The activity of 2',5'-oligoadenylate synthetase was elevated at the onset stage. Hypersensitivity to aspirin was confirmed by skin patch test and by lymphocyte stimulation test. Based on these findings, the patient was diagnosed with DIHS/DRESS caused by aspirin. To our knowledge, there have been no previous reports of aspirin-induced hypersensitivity syndrome subsequent to Kawasaki disease. The activity of 2',5'-oligoadenylate synthetase might be useful as a diagnostic marker of DIHS/DRESS syndrome and for exploring its pathogenesis.

Allergologische Diagnostik von Überempfindlichkeitsreaktionen auf Arzneimittel / Allergological approach to drug hypersensitivity reactions Leitlinie der Deutschen Dermatologischen Gesellschaft (DDG) und der Deutschen Gesellschaft für Allergologie und klinische Immunologie (DGAKI) in Zusammenarbeit mit dem Ärzteverband Deutscher Allergologen (ÄDA) und dem Berufsverband Deutscher Dermatologen (BVDD)Entwicklungsstufe 1 (S 1) Erstellungsdatum: 30.09.2007Nächste Überprüfung geplant: 1.10.2011

Zusammenfassung Überempfindlichkeitsreaktionen auf Arzneimittel müssen ausreichend geklärt werden mit dem Ziel, den Auslöser zu identifizieren. Die Anamnese umfasst neben der allgemeinen Anamnese auch Informationen zu angewandten Arzneimitteln, zur Klassifikation und zu den Umständen der Reaktion. Hauttests erfolgen bei allen Reaktionen mit Symptomen allergischer Überempfindlichkeiten mit geeigneten Testkonzentrationen, möglichst zwischen 4 Wochen und 6 Monate nach Abheilung der Reaktion durch Pricktest, Intrakutantest, Epikutantest oder Photopatchtest. Validierte Tests zum Nachweis spezifischer IgE-Antikörper im Serum sind nur für wenige Arzneistoffe (vor allem Betalaktamantibiotika) verfügbar; andere immunologische Labormethoden, z.B. der Basophilen-Aktivierungstest, werden nur in ausgewählten Fällen angewendet. Provokationstests sind indiziert, wenn der Auslöser durch bisherige Untersuchungen nicht mit Sicherheit identifiziert werden kann. Die Bewertung der Ergebnisse von Provokationstests sollte möglichst anhand objektiver Parameter erfolgen. Das Ergebnis der abschließenden Gesamtbeurteilung wird mit dem Patienten ausführlich besprochen und in einem Allergiepass niedergelegt.

An unusual case of immediate hypersensitivity reaction associated with an amalgam restoration

This report describes a case of immediate hypersensitivity reaction associated with the mercury component of amalgam restorations. The release of mercury induced an acute reaction which resulted in erythematous lesions, severe burning and itchy sensation and difficulty in breathing. Skin patch test results indicated a very strong positive reaction to mercury. Amalgam restorations were replaced with composite filling material. The patient, her family and her dental practitioner were strictly advised to use alternative restorative materials in case of a need for restoration.

Contact Allergy in Children Referred for Patch Testing

To determine the frequency of positive and relevant patch tests in children referred for patch testing in North America; to compare results of patch testing children and adults; and to compare our results with international data on contact allergy in children. Retrospective cross-sectional analyses of North American Contact Dermatitis Group (NACDG) data from January 1, 2001, through December 31, 2004. Patch test reactions for allergens that were positive and considered of clinical importance to the patient's eczematous problem were defined as being of current or past relevance. Clinical patch test data from 13 NACDG members, primarily a referral population. The pediatric population (hereafter referred to as "children") was defined as patients aged 0 to 18 years (n = 391). Patients 19 years and older constituted the comparison adult group (n = 9670). The frequency of positive patch test reactions and number of relevant ones. Secondary measures included the association of atopic markers, frequency of irritant reactions, and sources of relevant supplementary allergens. No significant difference in the overall frequency of at least 1 relevant positive patch test reaction was noted in children (51.2%) compared with adults (54.1%). The most frequent positive reactions in children were to nickel (28.3%), cobalt chloride (17.9%), thimerosal (15.3%), neomycin sulfate (8.0%), gold sodium thiosulfate (7.7%), and fragrance mix (5.1%). For children aged 0 to 18 the most frequent relevant positive reactions were to nickel sulfate (26.0%), cobalt (12.4%), neomycin (4.4%), fragrance mix (4.1%), gold (3.6%), and quaternium 15 (3.6%). The frequency of irritant reactions in adults and children was similar. Of the children with a relevant positive reaction, 34.0% had atopic dermatitis included as one of their final diagnoses, compared with 11.2% of adults (P < .001). Fifteen percent and 39% of children had relevant allergens not included in the NACDG series and a commercially available skin patch test (T.R.U.E. TEST [thin-layer rapid use epicutaneous test], panel 1.1 and 2.1; Allerderm, Phoenix, Arizona), respectively. Adults and children in this group are equally likely to have allergic contact dermatitis; frequency of relevant allergen reactions differs.

Contact sensitization in patients with chronic wounds: Results of a prospective investigation

It is well known that patients with chronic wounds frequently acquire clinically relevant contact sensitizations to skin care products. The aim of our study was to find out the actual frequency of contact sensitivities in patients with chronic wounds in Germany with particular attention to components of products used in modern wound therapy. We examined the results of a prospective clinical investigation on skin patch tests of patients with chronic wounds. Altogether, 45 patients with chronic wounds were tested. In 25 (55.5%) of the examined patients, contact sensitization to at least one substance was detected. The most frequent contact sensitizations were to PVP-iodine (20%), balsam of Peru (15.6%) patients, fragrance mix (11.1%), colophony (8.8%) and potassium dichromate (6.7%). We also found sensitization to the wound dressings Varihesive (11.1%), Iruxol N (6.7%) and Comfeel (2.2%). We would like to propagate that therapists who are involved in wound treatment should also pay attention on the ingredients of applied modern wound dressings.

Skin Tests in the Diagnosis of Drug Hypersensitivity Reactions

Adverse drug reactions (ADRs) are an area of concern for pharmaceutical drug development. Among these, drug hypersensitivity reactions are neither dose-dependent nor predictable, and affect only predisposed individuals. Clinical and immunological studies suggest that IgE-mediated (type I) and cell-mediated (type-IV) pathogenic mechanisms are involved in many immediate (i.e., occurring within 1 hour after the last drug administration) and non-immediate (i.e., occurring more than 1 hour after the last drug administration) hypersensitivity reactions, respectively. Skin prick, patch, and intradermal tests are the most readily available tools for the evaluation of hypersensitivity drug reactions. The diagnostic value of skin tests for many drugs still has not been fully established. Reliable skin test procedures for the diagnosis of drug hypersensitivity have been defined, and test concentrations have been validated for many drugs. Skin tests should be carried out according to the clinical features of ADRs. In immediate drug reactions, an IgE-mediated mechanism can be demonstrated by a positive skin prick and/or intradermal test after 20 minutes, whereas in non-immediate reactions, a T-cell involvement can be found by a positive patch test and/or a late-reading intradermal test. The predictive value of skin tests varies with the drug tested and is especially high with beta-lactams, muscle relaxants, insulins, platinum salts, streptokinase, and chymopapain. Further diagnostic tests are required in the assessment of drug hypersensitivity reactions. However, skin tests can provide information about the culprit drug and the mechanism involved in certain reactions. The present review addresses literature data regarding the diagnosis of drug hypersensitivity reactions by skin tests.

First large, multicenter, open-label study utilizing HLA-B*5701 screening for abacavir hypersensitivity in North America

A hypersensitivity reaction is associated with abacavir in approximately 2-8% of exposed patients. The frequency of the HLA-B*5701 allele varies across racial groups and significantly correlates with risk of hypersensitivity. Studies in Europe and Western Australia demonstrated that prospective screening can significantly reduce the rate of hypersensitivity by avoiding the use of abacavir in patients carrying the HLA-B*5701 allele. Prospective HLA-B*5701 screening in a large, racially diverse North American population resulted in less than 1% of individuals diagnosed with a suspected abacavir hypersensitivity reaction (ABC HSR) and no positive skin patch test through 30 weeks among HLA-B*5701-negative individuals.