Acute Generalized Exanthematous Pustulosis (AGEP)

Algorithm Steps

1. ▶

   Start

   Suspected AGEP

   Acute onset of numerous small non-follicular pustules on erythematous base

   1. ●

      Action

      Recognize Clinical Features

      Characteristic AGEP presentation

      • Dozens to hundreds of small (<5mm) sterile pustules
      • Non-follicular distribution
      • Arising on widespread edematous erythema
      • Facial/intertriginous areas often first affected
      • Fever >38°C common
      • Burning/pruritus
      • Onset: 1-11 days after drug (usually <5 days)
      1. ●

         Action

         STOP Causative Drug

         Identify and discontinue culprit medication

         • Most common: Aminopenicillins, quinolones, sulfonamides
         • Pristinamycin, hydroxychloroquine
         • Terbinafine, diltiazem
         • Macrolides, cephalosporins
         • Timeline: Usually within 48h of first dose (sensitized)
         • Or up to 11 days (first exposure)
         1. ◆

            Decision

            Differential Diagnosis

            Distinguish from other pustular conditions

            • Pustular psoriasis: History of psoriasis, slower evolution
            • Generalized pustular psoriasis: Recurrent, psoriasis history
            • Subcorneal pustular dermatosis: Chronic course
            • Bacterial folliculitis: Follicular pustules
            • DRESS: Fewer pustules, more organ involvement
            1. ●

               Action

               Apply EuroSCAR Validation Score

               Standardized diagnostic scoring

               • MORPHOLOGY: Typical pustules (+2), compatible (+1), insufficient (0)
               • DISTRIBUTION: Typical (+2), compatible (+1)
               • FEVER ≥38°C: Yes (+1), No (0)
               • NEUTROPHILS ≥7×10⁹/L: Yes (+1), No (0)
               • COURSE: Pustules resolve <15 days (+0), not compatible (-2)
               • HISTOLOGY: Exocytosis + pustules (+3), compatible (+2), other (-10)
               • TOTAL: ≤0=No AGEP, 1-4=Possible, 5-7=Probable, 8-12=Definite
               1. ●

                  Action

                  Diagnostic Workup

                  Laboratory and histologic evaluation

                  • CBC: Neutrophilia >7×10⁹/L typical, eosinophilia possible
                  • CMP: Usually normal, mild hepatic elevation possible
                  • Skin biopsy including pustule: Subcorneal/intraepidermal pustules
                  • Histology: Papillary edema, neutrophilic + eosinophilic infiltrate
                  • Pustule culture: STERILE (not infected)
                  1. ●

                     Action

                     Mild AGEP

                     Limited extent, stable patient

                     • Outpatient management possible
                     • High-potency topical corticosteroids
                     • Emollients for desquamation phase
                     • Antipyretics for fever
                     • Close follow-up
                     1. ●

                        Action

                        Supportive Treatment

                        Symptomatic care for all patients

                        • Topical corticosteroids (potent) for inflammation
                        • Antiseptic baths/cleansers
                        • Emollients during desquamation phase
                        • Antihistamines for pruritus
                        • Antipyretics (acetaminophen) for fever
                        1. ●

                           Action

                           Course and Monitoring

                           AGEP is self-limiting

                           • Pustules resolve spontaneously in <15 days
                           • Desquamation follows (collarette scaling)
                           • Complete resolution typically by 2-3 weeks
                           • No scarring expected
                           • Document culprit drug
                           1. ●

                              Action

                              Allergy Workup (After Resolution)

                              Patch testing to identify culprit

                              • Perform 6 weeks to 6 months after resolution
                              • Patch test sensitivity: ~58% (higher than SJS/TEN)
                              • Identifies causative drug for future avoidance
                              • Document results in medical record
                              • Allergy card for patient
                              1. ✓

                                 Outcome

                                 Resolution

                                 Excellent prognosis

                                 • Complete recovery expected
                                 • Mortality <5% (rare systemic involvement)
                                 • No long-term sequelae
                                 • Recurrence if re-exposed to culprit
                           2. ⚠

                              Warning

                              Rare Complications

                              Uncommon but reported

                              • Hepatic involvement (rare)
                              • Renal involvement (rare)
                              • Pulmonary involvement (rare)
                              • Secondary bacterial infection
                              • If systemic: Manage supportively + consult derm
                  2. ●

                     Action

                     Moderate-Severe AGEP

                     Extensive involvement or systemic symptoms

                     • Admission may be required
                     • Systemic corticosteroids: Prednisone 0.5-1 mg/kg/day
                     • Monitor for rare internal organ involvement
                     • Fluid/electrolyte support if extensive skin loss
                     • Secondary infection surveillance