Malassezia Folliculitis following Triple Therapy for Cystic Fibrosis

Abstract

Triple-combination therapy with elexacaftor, tezacaftor and ivacaftor has been recently approved for cystic fibrosis patients with at least one F508del mutation in the transmembrane conductance regulator of the cystic fibrosis gene. Among the adverse events of elexacaftor, tezacaftor and ivacaftor, the cutaneous ones have been rarely reported, mainly dealing with urticarial-like rashes. On this topic, we report two cases of Malassezia folliculitis following triple therapy administration in two young females. In the first patient, a papulopustular rush appeared before the folliculitis while in the second patient it was not preceded by other skin manifestations. The diagnosis was confirmed both by dermoscopy and histology. The prompt response to systemic antimycotic drugs provided further evidence for the causative role of Malassezia, requiring no discontinuation of cystic fibrosis therapy. We could hypothesize that the triple regimen treatment may induce changes in the skin microbiome, potentially able to favor colonization and proliferation of Malassezia species. Physicians should be aware of such associations to allow prompt diagnosis and early interventions, avoiding useless drug removal.

Keywords: Malassezia; adverse drug reaction; cystic fibrosis; elexacaftor/tezacaftor/ivacaftor; folliculitis; microbiome; skin.

Figure 1

(a) First rash: plethora of erythematous pinhead-sized papular lesions, many of which were centered by follicular pustules; (b) second rash: papulopustular lesions involving décolleté with hypopigmented macules and patches of pityriasis Versicolor; (c) Dermoscopy (10×) of a folliculocentric pustule with surrounding erythema; (d) PAS (40×) re-vealed spherical to oval yeast-like organisms.

Figure 2

(a) Malassezia folliculitis involving the back; (b) dermoscopy (10×) shows follicular pustule with surrounding erythema; (c) H-E stain (20×) reveals features of folliculitis with dilatation of the infundibulum and plugging of the follicular ostium with keratin and cellular debris. (d) Silver methenamine stain (20×) highlights a ruptured follicle containing numerous Malassezia yeasts.