100560 - Atypical Presentation of AGEP Highlighting the Overlapping Spectrum of Severe Cutaneous Adverse Reactions

Acute Generalized Exanthematous Pustulosis (AGEP) is a rare cutaneous adverse

reaction characterized by rapid development and dissemination of sterile,

nonfollicular pustules on an erythematous base, most commonly triggered by

medications. Its clinical presentation and course are generally distinctive, allowing

differentiation from other delayed T-cell mediated severe cutaneous adverse

reactions. However , atypical and overlapping presentations of AGEP have been

increasingly recognized.

We present this case of a 21-year old woman with insulin-dependent diabetes

mellitus presented to the emergency department with a five day history of fever

and neck swelling, accompanied by abdominal pain and vomiting for one day. Initial

evaluation revealed diabetic ketoacidosis and an abscess on her neck with

purulent discharge. On examination she was tachycardic, but hemodynamically

stable. Given a reported history of mild skin reaction to ceftriaxone, she was

started on intravenous nafcillin and vancomycin. The next day, the patient

developed an erythematous, pruritic rash on her arms and chest, with pinpoint

pustules, accompanied by facial swelling, fever , tachycardia, and low blood

pressure. Nafcillin was discontinued and replaced with aztreonam. On day three,

the abscess was drained; however , she remained febrile and hypotensive, with

rising leukocytosis. Her rash spread over her trunk, back, neck, and arms with new

vesicular lesions. On day four , the patient's rash worsened with new bullae,

desquamation, neutrophilia, and fever . Vancomycin was discontinued. Punch

biopsies were obtained, and the patient was started on intravenous immunoglobulin

as well as topical and systemic steroids. Histopathology demonstrated subcorneal

and superficial intraepidermal pustule formation, mild spongiosis, marked papillary

dermal edema, and focal epidermal degeneration with some separation of stratum

corneum, consistent with AGEP. A week later , she had only mild desquamation and

her condition continued to improve. Patient was labeled to have an allergic

reaction to vancomycin and nafcillin. She was referred to Allergy/Immunology clinic

for further evaluation.

This case highlights an atypical AGEP presentation, reinforcing the clinically

overlapping spectrum with other adverse reactions like SJS/TEN, which poses a

challenge to physicians. Awareness of atypical presentations along with early

histological investigation when indicated, can aid in the accurate diagnosis and

timely management of such cases.