Clinical classification of DHRs
Tiny changes were made through clinical classification of DHRs, but
controversies still exist. Immediate reactions (IRs) appear within 1
hour up to 6 hours, after the first dose of the last therapeutic course.
In general IRs are mediated by IgE antibodies. The clinical
manifestation of those reactions ranges from benign urticaria with or
without angioedema, up to potentially life-threatening anaphylaxis. Two
clinical entities of IRs have been proposed: mild IRs (urticaria
/angioedema), and severe IRs (anaphylaxis/anaphylactic shock). IRs can
also be mediated by COX-1 inhibition or by MRGPRX2 (Mas-related
G-protein-coupled receptor member X2). Clinical entities are: urticaria,
angioedema, anaphylaxis and respiratory symptoms. Nonimmediate reactions
(NIRs) occur more than 6 hours after the first dose of the last
therapeutic course, which often start 2 to 5 days later. NIRs are
mediated by T cells. Clinical manifestations of those reactions ranges
from benign rashes (maculopapular exanthema-MPE or fixed drug eruption-
FDE or serum sickness like reactions SSLR) to potentially
life-threatening severe cutaneous adverse reactions (SCARs) such as
Stevens-Johnson syndrome-SJS and toxic epidermal necrolysis-TEN, drug
reaction with eosinophilia and systemic symptoms-DRESS, acute
generalized exanthematous pustulosis-AGEP or single organ reaction such
as drug induced liver disease (DILI). Also two clinical entities of NIRs
have been proposed: mild NIRs (MPE, SSLR) and severe NIRs
(SCARs).1-3