Skin Testing and Patch Testing in Non-IgE-Mediated Drug Allergy

Abstract

Drug skin tests can reproduce delayed hypersensitivity to drugs and entail a moderate reexposure of patients to offending drugs. Drug patch tests (DPTs) and prick tests can be done with any commercialized form of a drug. In non-severe delayed non-IgE-mediated reactions to drugs, intradermal tests (IDT) with delayed readings have a greater value, but their techniques lack standardization. A negative drug skin test does not exclude the responsibility of a drug, and the drug must be rechallenged in non-severe cases. DPTs are useful in maculopapular rashes, flexural exanthemas, and if done in situ, also in fixed drug eruption. Their best indication is in acute generalized exanthematous pustulosis or drug reaction with eosinophilia and systemic symptoms (DRESS). They should be carried out cautiously, following strict guidelines. Prick tests have a low value but they can sometimes be positive on delayed readings. In non-severe delayed reactions to drugs, intradermal tests with delayed readings are the most sensitive skin tests especially for beta-lactam antibiotics, radiocontrast media, heparins but also some biological agents. The value of patch testing varies according to the implicated drug and the non-immediate adverse drug reaction. In DRESS, DPTs have a good value in testing carbamazepine or proton pump inhibitors but remain negative in testing with allopurinol or salazopyrin. In toxic epidermal necrolysis, DPTs are safe but positive in only 9 to 23 % of the reported cases.

A Comparative Analysis Between Antibiotic- and Nonantibiotic-Associated Delayed Cutaneous Adverse Drug Reactions

“…Although the sensitivity of in vivo skin testing, in particular patch testing, for some SCAR syndromes is poor (approximately 20% for SJS/TEN), it can be up to 80% for others such as DRESS. 21,22 Future validation of ex vivo T-cell enzyme-linked immunospot assays, which have primarily been explored in antiretroviral hypersensitivity, 23,24 may allow assignment of drug causality whilst avoiding in vivo testing, which is both contraindicated and potentially unhelpful in acute SJS/TEN/ DRESS. [23][24][25][26] Multidisciplinary approaches that include detailed clinical appraisal, ADR Committee review, utilization of SJS/ TEN scoring systems (eg, ALDEN), in vivo skin testing, and ex vivo assays are required to ensure accurate causality assessments.…”

A Case of Acute Generalised Exanthematous Pustulosis Induced by Paracetamol

“…Özellikle multipl ilaç rejimlerinde sadece zamanlama ve hikayeye dayanarak sorumlu ajanı bulmak zordur. Bu nedenle ilaç deri testleri ilacın kendisini veya içerdiği maddeyi bulmada yardımcı olabilir (15).…”

“…İntradermal testler sorumlu ajanı bilinmeyen ya da ilaç kullanım zamanına göre düşük ihtimalli bir ilacı bulunan ve multipl ilaç rejimi alan sınırlı sayıda hastada kullanılır (15). AGEP, ayırıcı tanıda en çok jeneralize püstüler psöriazis (GPP) ile karışmaktadır (17).…”

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

“…For patch tests; the commercially available test drugs were prepared at concentrations of 5, 10 and 30 % in petrolatum, in accordance with the reported maximum non-irritant concentrations [21]. Initial tests were applied at much lower concentrations in severe allergic reactions, such as Stevens-Johnson syndrome (SJS) characterised by extensive detachment of epidermis and erosions of mucous membranes and Drug reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome characterised by skin rash, fever, lymph node enlargement and internal organ involvement.…”

“…Initial tests were applied at much lower concentrations in severe allergic reactions, such as Stevens-Johnson syndrome (SJS) characterised by extensive detachment of epidermis and erosions of mucous membranes and Drug reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome characterised by skin rash, fever, lymph node enlargement and internal organ involvement. [17,21]. Finn-chambers were used for application and were filled with 20-30 lL of the drug suspension.…”