The necessity of patch testing in determining the causative drug of AGEP

Abstract

AGEP is an acute form of eruption in which multiple nonfollicular sterile pustules develop in the presence of erythema and edema.There is usually fever and peripheral blood leukocytosis. [1][2][3] The rashes appear hours or days after exposure to the drugs and disappear spontaneously within 1-2 weeks of cessation. 3 A rough estimate of the incidence of AGEP cases is 1-5 per million every year. Although AGEP mostly affects adults, it can be seen in all age groups. In a study including 97 validated cases of AGEP, the

Acute Generalized Exanthematous Pustulosis: Clinical Features, Differential Diagnosis, and Management

“…AGEP is estimated to occur in one to five people per million per year [ 7 , 8 ]. AGEP has been reported more frequently in women, with a mean age of 56 years [ 8 , 9 ].…”

“…AGEP is estimated to occur in one to five people per million per year [ 7 , 8 ]. AGEP has been reported more frequently in women, with a mean age of 56 years [ 8 , 9 ]. AGEP has been associated with increased body mass index; the mechanism may be related to upregulated proinflammatory cytokines secondary to obesity [ 10 , 11 ].…”

“…Hydroxychloroquine is the next most frequently implicated drug reported after antibiotics as a whole, with 44 cases reported in a recent review [ 52 ]. Particularly in the era of the coronavirus disease 2019 (COVID-19) pandemic from 2020 to present, there have been increased reports of hydroxychloroquine-induced AGEP, which may be secondary to increased use of the drug [ 8 , 53 – 68 ]. Of note, hydroxychloroquine-induced AGEP typically has a delayed onset compared with other drugs due to its long half-life of 40–50 days [ 69 ].…”

“…AGEP typically presents within 24–48 h of ingestion of the offending drug, with a median time of 24 h for antibiotics in particular. However, some drugs have been shown to have a lag time of up to 10–22 days; therefore, this is not a defining feature [ 2 , 8 ]. Prodromal signs include fever (>38°C) and generalized malaise with leukocytosis, particularly neutrophilia, with eosinophilia in up to 30% of patients [ 2 ].…”

“…This scoring tool classifies patients with suspected AGEP as having definite, probable, possible, or no AGEP (Table 2 ). A drug patch test can be used to identify the cause of AGEP [ 8 ]. It is recommended that these tests are generally performed no sooner than 4 weeks after the resolution of AGEP but within 1 year after the adverse reaction [ 185 ].…”