Ritonavir-boosted
darunavir (DRV/r) is a
protease inhibitor widely used in the treatment of HIV-1
infection. However,
skin rash is a well-known adverse event of DRV, and limited data are available from observational settings. This observational study examined the characteristics of DRV-induced
skin rash in treatment-naïve patients who commenced once-daily DRV/r-containing antiretroviral
therapy (ART). Of the 292 study patients, DRV rashes developed in 31 (11%) patients with a median latency of 10 days (developing from 7 to 14 days in 93%) from initiation of ART. DRV
skin rash was generally mild, as only one patient (3%) had grade 3
rash whereas 24 (77%) patients had grade 2 and 6 (19%) patients had grade 1. Only two patients (7%) discontinued DRV/r due to
skin rash, and the other continued DRV/r and their rashes disappeared completely without any complications. Interestingly, DRV
rash occurred more frequently to patients with less advanced HIV-1
infection than those with advanced
infection. The incidence of DRV
rash was not significantly different between patients with and without history of
sulfonamide allergy (p = 0.201). Furthermore, when we exclude patients without history of
sulfonamide use and only examine patients with
sulfonamide use (n = 145), the result was similar (p = 0.548). In conclusion, DRV rashes were frequently observed but the prognosis was benign. Most patients tolerated DRV rashes with use of oral
steroid or
antihistamine without discontinuation of DRV. To date, there is no clear clinical evidence to suggest that DRV should be avoided in patients with history of
sulfonamide allergy.