Ribavirin
Ribavirin is used in combination with pegylated-interferon α2a
(peg-IFN-α2a) for treating chronic hepatitis C, and both have been
associated with several cutaneous DHRs (49). Ribavirin alone causes
dermatitis, alopecia, and photoallergic eczematous reactions (50,51),
and the risk of DHR increases with combination therapy: rash [response
rate (RR,1.74; 95% confidence interval (CI), 1.17-2.6), dermatitis (RR,
1.67; 95% CI, 1.21-2.30), and pruritus (RR, 1.62; 95% CI,1.29-2.02)
(52). A meta-analysis revealed that, on combination therapy, mild to
moderate cutaneous reactions appear in 13.3% of patients, localized
cutaneous reactions in 2.6%, generalized reactions-pruritus, skin
xerosis and eczematous changes in 10.3%, alopecia in 4.1%, and
exacerbation of lichen planus in less than 1% (43).
The etiological diagnosis is difficult in case of combination therapy. A
drug provocation test (DPT) confirmed the diagnosis of ribavirin
hypersensitivity in a patient having MPE due to combined use of
peg-IFN-α2a and ribavirin (53). In
another case, an erythema multiforme type drug eruption occurred with
peg-IFN-α2a, ribavirin and/or fluvastatin sodium therapy and a positive
lymphocyte transformation test (LTT) confirmed the diagnosis of
ribavirin hypersensitivity (54).
Successful desensitization protocols were reported (55,56).