Fixed drug eruption occurring in vitiliginous skin

Painful and Pruritic Blisters on the Lower Lip

“…It should be carefully performed, especially in patients with multiple lesions, because of the risk of severe reactions and new lesions with repeated exposure to the causative drug. 8 It should not be performed for a generalized bullous fixed drug eruption. The protocol involves administration of very small doses of the implicated drug with a gradual increase in dose (eg, 1/10, 1/8, 1/4, 1/2, and full therapeutic dose) until reaction is observed at the site of fixed drug eruption.…”

“…For instance, carbocysteine-induced fixed drug eruption requires more than 2 days to elicit the eruption, as the hypersensitivity is usually to a metabolite. 8 Patch testing, in which the results are positive on previously lesional skin and negative on nonlesional skin, has been suggested as an alternative diagnostic method; however, positive responses occur in only about 40% of fixed drug eruption cases. The falsenegative result might be attributable to the fact that the hypersen-sitivity reaction is not to the drug but rather to a metabolite, which would only form after oral ingestion.…”

S-Carboxymethyl-L-cysteine-induced Fixed Drug Eruption

“…Although SCMC is used in a wide range of age groups, from infants to elderly patients, few instances of cutaneous adverse drug reactions (cADRs) have been reported (2,3,5,6). Takahashi & Fukuda (7) aggregated 65 cases of SCMC-induced cADRs that have been reported in Japan.…”

Maculopapular rash to S‐carboxymethylcysteine‐lysine (carbocisteine)

“…It is a mucoregulatory drug 2 used to treat chronic obstructive pulmonary disease (COPD) 1 . Although S‐CMC is used for treatment of patients in all ages, from infants to elderly, few cutaneous reactions to this drug have been reported; the most frequent are delayed allergic skin reactions such as fixed drug eruption (FDE) 2‐4 …”