Keywords: CF, cystic fibrosis; ELX/TEZ/IVA, elexacaftor/tezacaftor/ivacaftor; EM, erythema multiforme; UM, urticaria multiforme; cystic fibrosis; drug rash; elexacaftor; ivacaftor; morbilliform drug eruption; tezacaftor; urticaria; urticaria multiforme.