Reações alérgicas a medicamentos

Abstract

Objective: This review addresses the most recent published literature regarding drug allergy, in order to provide physicians with a background for a better understanding of this problem of great relevance for public health. Sources of data:The sources of data for obtaining the original and review articles published in the last 10 years were MEDLINE, Pubmed and Lilacs. The articles chosen for this review relate drug allergy to immunological mechanisms, epidemiology, clinical and laboratory evaluation, skin lesions, clinical management, and re-exposure to the drug.Summary of the findings: Allergic reactions represent one third of adverse drug reactions. They are considered rare but with high morbimortality. Gell & Coombs definition has been useful for classifying some types of drug allergic reactions; however, some still remain without classification because of poor knowledge of the mechanisms involved. The existence of T cell subpopulations with diverse characteristics reveals the complexity of the subject and, at the same time, elucidates several questions raised about it. It was recently postulated a new concept of chemically inert drug presentation to T cells, restricted to the major histocompatibility complex, but in a non-covalent and labile way. In clinical practice, without adequate laboratory tests, it is difficult to correlate clinical symptoms and immunological mechanisms. In vitro and in vivo skin tests have been employed in cases of suspected drug allergy reaction. However, there are very few commercially available reagents.Conclusions: Drug allergy constitutes an important problem in adverse drug reactions because of its potential of morbidity and mortality. It is necessary to emphasize the relevance of pharmacovigilance during treatment of patients, as well as the identification of possible immunological mechanisms involved in the events, through laboratory tests and detailed history and clinical evaluation.

Síndrome de Stevens-Johnson e Necrólise Epidérmica Tóxica em um hospital do Distrito Federal

“…Não é incomum desenvolver pneumonia (15) . As bolhas geralmente não determinam descolamento epidérmico maior do que 10% da superfície corpórea (11,16) .…”

“…A distinção entre a SSJ e a NET, do ponto de vista clínico, se realiza pela percentagem de área com erupções cutâneas ou passível de erosão com sinal de Nikolsky (SN) positivo, calculada em termos de superfície corporal (12) . Segundo a literatura, a SSJ acomete ≤10% da superfície corporal; a ocorrência simultânea de SSJ e NET pode comprometer 10 a 30% da epiderme; e a NET atinge área ≥30% da superfície corporal (13)(14)(15)(16) . O SN representa o deslocamento da camada superficial da epiderme mediante uma fricção ou trauma leve.…”

“…As complicações mais frequentes da SSJ e da NET, segundo a literatura, são a sepse, que, quando não reconhecida e tratada, pode levar ao óbito; e a ceratoconjuntivite, que pode prejudicar a visão e resultar em retração conjuntival, cicatrização e lesão da córnea (16) . Entre as sequelas mais comuns na fase tardia da NET, citam-se a hiper ou hipopigmentação da pele (62,5%), as distrofias das unhas (37,5%) e as complicações oculares, dentre as quais se destacam: olhos secos (46,0%), triquíase (16,0%), simbléfaro (14,0%), distiquíase (14,0%), perda da visão (5,0%), entrópio (5,0%), ancilobléfaro (2,0%), lagophthalmos (2,0%) e ulceração da córnea (2,0%).…”

Implementation of a penicillin allergy skin test

“…Drug allergy is induced by immunogenic determinants from the drugs or their metabolites, generally conjugated to proteins (Nagao- Dias et al, 2004). For 568 instance, it is known that penicillin presents a major determinant (benzylpenicilloyl group or BPO) and a minor determinants mix (MDM, constituted by benzylpenicilloate, benzylpenicilloyl-amine, and benzylpenicilloic acid, among others).…”

Identification of new minor metabolites of penicillin G in human serum by multiple‐stage tandem mass spectrometry

“…The allergic reactions do not result from known toxicological properties of the drug, but from immune reactions to the parent drug or to its metabolites 7. Among a wide variety of antimicrobial agents, β‐lactams, especially penicillins, are the most frequently prescribed drugs, and the one that most commonly cause allergies 8, 9. Thus, the allergic drug reaction to the β‐lactam antibiotics is a major factor limiting their use.…”