Terbinafine is an
allylamine antifungal agent, effective in the treatment of
dermatomycoses. Many cutaneous adverse reactions have been reported (in about 3% of treated patients). Furthermore
terbinafine has been associated with pustular eruptions, as well as the induction and exacerbation of pre-existing
psoriasis and
acute generalized exanthematous pustulosis (AGEP). AGEP is an uncommon aseptic pustular eruption, classified for many years as a pustular
psoriasis, that usually follows recent administration of oral or parenteral drugs. The disease is most frequently triggered by
antibiotics, most of all aminopenicillins and
macrolides. Characteristic AGEP features include the sudden onset of
fever above 38 C with widespread erythematous eruption, rapidly progressing to a fine, non-follicular, micropustular
rash. Leucocytosis is generally present, sometimes associated with
eosinophilia. The illness usually resolves spontaneously with the
fever and the pustulation clearing within 15 days, sometimes followed by desquamation. Hystopathology shows non-follicular spongiotic pustules in the epidermis filled with neutrophils, a mixed perivascular infiltrate of neutrophils and occasional eosinophils with papillary dermal oedema. On this subject, Sideroff et al. recently elaborated a validation score based on morphology, histological criteria, and disease course. The pathogenetic mechanism which leads to the induction of AGEP by some medicines has still not been clarified, but T cells seem to play a crucial role. The authors report a case of a patient with
terbinafine-induced AGEP and a review of the literature about this topic. The case illustrates once again the role of
terbinafine in AGEP and reminds us that early diagnosis of AGEP is important to avoid unnecessary investigations and/or the administration of
antibiotics.