Received Mar 1, 2026
| Type | Name | Manufacturer | Dose | Lot | Route / Site |
|---|---|---|---|---|---|
| FLUX | INFLUENZA (SEASONAL) (NO BRAND NAME) | UNKNOWN MANUFACTURER | UNK | — | OT |
DRESS syndrome; generalized pruritic rash; fever; dyspnea; fatigue; anorexia; diffuse maculopapular rash; significant eosinophilia; perivascular lymphocytic infiltrate with numerous eosinophils; drug induced hypersensitivity reaction; <p>Introduction: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is a rare, potentially life-threatening hypersensitivity reaction marked by fever, rash, hematologic abnormality, and multiorgan involvement. While most commonly triggered by medications such as antiepileptics and allopurinol, DRESS syndrome has rarely been associated with vaccinations. Case Description: A 90-year-old woman developed generalized pruritic rash two days after receiving a seasonal influenza vaccine. Over the next two weeks, she experienced fever, dyspnea, fatigue, and anorexia. She was admitted to the hospital with concern for pneumonia and placed on antibiotics. Notable on the exam was a diffuse maculopapular rash, significant eosinophilia (up to 3400 per mL), elevated inflammatory markers, and elevated transaminases. Infectious and autoimmune workups were negative. Skin biopsy demonstrated a perivascular lymphocytic infiltrate with numerous eosinophils, consistent with a druginduced hypersensitivity reaction. She was diagnosed with DRESS syndrome and started on systemic corticosteroids with significant improvement in rash and eosinophilia. She was ultimately transitioned to mepolizumab for its steroid-sparing effect given her age and concern for systemic steroid side effects. She eventually completed 6 months of mepolizumab with complete resolution of symptoms and eosinophilia. She was counseled to avoid future influenza vaccinations. Discussion: This case highlights the potential of influenza vaccines to act as rare but serious triggers of DRESS syndrome. Early detection and treatment with corticosteroids are crucial for favorable outcomes. With increasing vaccination efforts in older adults, clinicians should maintain a high index of suspicion for DRESS in patients presenting with systemic symptoms and rash following immunization. Rash of DRESS on lower extremities (left) before treatment and resolution of rash (right) after treatment for comparison.</p> Initial information received on 23-Feb-2026 via other healthcare professional regarding an unsolicited valid serious case issued from a literature article This case involves a 90 years old female patient who experienced DRESS syndrome while receiving vaccine Influenza Vaccine (latency: 2 days). The patient's past medical history, medical treatment(s), vaccination(s) and family history were not provided. The patient developed generalized pruritic rash (pruritic rash) two days after receiving a seasonal influenza vaccine (dose, form, frequency, strength, route: unspecified). Over the next two weeks, she experienced fever (pyrexia), dyspnea (dyspnoea), fatigue, and anorexia (decreased appetite). She was admitted to the hospital with concern for pneumonia and placed on antibiotics. Notable on the exam was a diffuse maculopapular rash (Rash maculo-papular), significant eosinophilia (eosinophilia) (up to 3400 per mL), elevated inflammatory markers, and elevated transaminases. Infectious and autoimmune workups were negative. Skin biopsy demonstrated a perivascular lymphocytic infiltrate with numerous eosinophils (Lymphocytic infiltration), consistent with a drug induced hypersensitivity reaction (Hypersensitivity). She was diagnosed with DRESS syndrome (Drug reaction with eosinophilia and systemic symptoms) and started on systemic corticosteroids with significant improvement in rash and eosinophilia. She was ultimately transitioned to mepolizumab for its steroid-sparing effect given her age and concern for systemic steroid side effects. She eventually completed 6 months of mepolizumab with complete resolution of symptoms and eosinophilia. She was counseled to avoid future influenza vaccinations. This case highlights the potential of influenza vaccines to act as rare but serious triggers of DRESS syndrome. Early detection and treatment with corticosteroids are crucial for favorable outcomes. With increasing vaccination efforts in older adults, clinicians should maintain a high index of suspicion for DRESS in patients presenting with systemic symptoms and rash following immunization. Rash of DRESS on lower extremities (left) before treatment and resolution of rash (right) after treatment for comparison. Information regarding batch number and expiration date corresponding to the one at time of event occurrence was requested. Seriousness Criteria: Medically significant Action taken: Not applicable Corrective Treatment: systemic corticosteroids and mepolizumab Outcome: Recovered Reporter Causality: related; Sender's Comments: Sanofi company comment dated 28-FEB-2026- This case involves a 90-year-old female patient who developed Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS syndrome) following administration of seasonal Influenza Vaccine. The patient experienced pruritic rash with onset two days post-vaccination, followed by pyrexia, dyspnoea, fatigue, and decreased appetite over two weeks. Clinical examination revealed maculopapular rash, marked eosinophilia (3400 per mL), elevated inflammatory markers, and transaminases elevation. Skin biopsy confirmed perivascular lymphocytic infiltration with eosinophils, supporting drug-induced hypersensitivity. The temporal relationship is strongly suggestive, with symptom onset occurring within 48 hours of vaccine administration and progressive manifestation consistent with DRESS syndrome's typical presentation. Upon dechallenge with initiation of systemic corticosteroids followed by mepolizumab, complete resolution of symptoms and eosinophilia occurred after six months of treatment. Infectious and autoimmune workups were negative, eliminating alternative etiologies. However, the patient's complete medical history, concomitant medications, and specific vaccine details (batch, formulation) are unavailable, limiting comprehensive assessment. Despite these information gaps, the characteristic clinical presentation, temporal association, positive dechallenge, histopathological confirmation, and exclusion of alternative causes support that the role of Influenza Vaccine in causing DRESS syndrome cannot be excluded.
Test Name: Skin Biopsy; Result Unstructured Data: Skin biopsy demonstrated a perivascular lymphocytic infiltrate with numerous eosinophils, consistent with a drug induced hypersensitivity reaction; Test Name: Eosinophil count; Test Result: 3400 {DF}; Result Unstructured Data: significant eosinophilia; Test Name: inflammatory markers; Result Unstructured Data: elevated inflammatory markers; Test Name: exam; Result Unstructured Data: was a diffuse maculopapular rash and elevated transaminases. Infectious and autoimmune workups were negative