Evaluation of preliminary patch testing in patients with suspected adverse drug reactions in a tertiary care hospital, Kancheepuram District: A Cross Sectional study

Mariette Teenu Pious, (2021) Evaluation of preliminary patch testing in patients with suspected adverse drug reactions in a tertiary care hospital, Kancheepuram District: A Cross Sectional study. Masters thesis, Karpaga Vinayaga Institute of Medical Sciences, Madhuranthagam.

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INTRODUCTION: Adverse drug reactions (ADR) are defined by the WHO as “any nox-ious, unintended and undesired effect of a drug that occurs at doses for any diagnosis and treatment”. Cutaneous adverse drugs reactions (CADRs) are common among the ADRs. They cause plenty of sufferings, hospitalization and economic burden, and sometimes can also be fatal. The clinical incidence of ADR s is usually between 3-6% among outpatients and around almost 15 % in hospitalized patients serving as a frequent cause for consultation in dermatology. Skin tests are the most readily available method of allergy testing for CADR to dermatologists. Josef Jadassohn is considered to be the founder of Patch Testing in 1895, Professor of the Breslau university, later expanded and enhanced in technique by Bruno Broch, a dermatology pioneer. Patch testing helps to recreate an allergic reaction to nonirritating concentrations of an allergen that is suspended in a vehicle testing with the suspected element and helps to determine the cause and pathophysiological mechanisms of a CADR. CONCLUSION: 1. Patch testing has been found to be of great diagnostic significance in the evaluation of drug sensitivity in cases of AGEP, Maculopapular ex-anthema, SJS/TEN, FDE and beta lactam antibiotics by > 50%. 2. The highest number of positive cases was for antibiotics (23%)followed by sulfonamides (19%). A higher number of cases with paracetamol sen-sitivity has been noted (12%) which is unique to this study followed by even vitamin E (4%) and cpm (3%) allergies. Antifungals were found to be the least reactive among the tested drugs. 3. The negative predictive value is of more value than other statistical prob-abilities for patch testing. 4. In patients with not a very definitive history of drug allergy or urticaria due to prescribed medications patch testing can be done as a screening procedure to rule out the causative drug. 5. Commercialised preparations of drugs brought by the patient seems to have some significance over the reactions elicited by the pure forms of the same drug. A wide range of drugs can be tested by this method. 6. The drug hapten model proposed by Pichler suggesting a covalent inter-action between the HLA and drug, modifying the antigen binding site and peptide ligands that can be presented to the T cells has been studied extensively by trials based on patch testing. This model provides an exciting preview into the future of pharmaceuticals which can manufacture drugs not interacting with the human leucocyte antigen thus eradicating adverse drug reactions and providing safe drugs. 7. Patch testing along with clinical diagnosis has been said to give unto a 100% negative predictive value. Hence patch testing can be safely recommended as a screening tool in regular opd procedures and prescriptions especially in patients with a suspicion to previous sensitivity reactions to unknown drugs. A positive patch test can further be followed by drug challenge test and serum IgE antibody levels / RAST or basophil activation tests. 8. A new drug testing panel with a complete set of all dermatological and routine opd prescription drugs prepared according to standard guidelines has to be formulated and made available for routine clinician use.

Item Type: Thesis (Masters)
Additional Information: 201830451
Uncontrolled Keywords: Preliminary patch testing, adverse drug reactions, tertiary care hospital, Kancheepuram.
Subjects: MEDICAL > Dermatology Venereology and Leprosy
Depositing User: Subramani R
Date Deposited: 02 Oct 2021 15:04
Last Modified: 02 Oct 2021 15:04
URI: http://repository-tnmgrmu.ac.in/id/eprint/18455

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