Comparison of Acute Generalized Exanthematous Pustulosis with Maculopapular Rash in a Swiss Patient Cohort: A...

Acute generalized exanthematous pustulosis (AGEP) is a rare cutaneous drug reaction characterized by the sudden appearance of non-follicular sterile pustules on an erythematous background which is accompanied by fever and peripheral blood neutrophilia. While the clinical differentiation between AGEP and common delayed-type drug hypersensitivity reactions, such as maculopapular rash (MPR), is well defined, the pathomechanism, causative drugs, and other possible contributing factors remain poorly studied to date.

In this retrospective case-control study, we compared clinical data on suggested causative drugs, drug testing, and comorbidities between a group of 52 patients with a confirmed diagnosis of AGEP (both clinically and histologically) and a group of 63 patients with confirmed MPR.

Evaluation of the causative drugs revealed that beta-lactam antibiotics represent the most common culprit drug in both AGEP and MPR, while antimycotics (p = 0.002), glucocorticoids (p = 0.0106) and NSAIDs (p = 0.0064) were significantly more frequent in AGEP. Skin patch tests and in vitro lymphocyte transformation tests (LTTs) showed higher positivity rates in MPR compared to AGEP, with all non-beta-lactam antibiotics tested with LTT leading to negative results in AGEP. A detailed analysis of comorbidities suggested a possible association between diseases of the upper gastrointestinal tract and AGEP.

This study highlights the differences in causative drugs and comorbidities between AGEP and MPR, emphasizing the need for further research to enhance the understanding and management of AGEP.