Surreal illustration of DRESS/DIHS diagnostic challenges.

Levofloxacin Alert: When the Cure Causes a Crisis

Nico Varela in Health & Wellness December 2025 • 4 min read.

"Understanding DRESS/DIHS, a rare but serious reaction to a common antibiotic, and its connection to autoimmune conditions."

Antibiotics are essential weapons in our fight against bacterial infections. Levofloxacin is a common antibiotic prescribed for a range of conditions. However, like all medications, it carries the risk of side effects. In rare instances, it can trigger a severe and potentially life-threatening reaction known as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also referred to as Drug-Induced Hypersensitivity Syndrome (DIHS).

DRESS/DIHS is characterized by a constellation of symptoms, including fever, skin rash, internal organ involvement, and abnormal blood cell counts (eosinophilia). It typically emerges 2 to 6 weeks after starting the medication, but can be difficult to diagnose due to its varied presentation and overlap with other conditions.

This article will explore a specific case highlighting the challenges of diagnosing levofloxacin-induced DRESS/DIHS in a patient with pre-existing autoimmune conditions. We'll delve into the symptoms, diagnostic process, and the importance of awareness among both patients and healthcare providers.

Unmasking DRESS/DIHS: A Case Study

Surreal illustration of DRESS/DIHS diagnostic challenges.

A 77-year-old woman with a history of systemic scleroderma (SSc), rheumatoid arthritis (RA), and Sjogren's syndrome (SjS) was admitted to the hospital with high fever, shortness of breath, and a widespread red rash (erythroderma). Prior to admission, she had been treated with intravenous levofloxacin for a cough and fever. While initial oral levofloxacin seemed to resolve her symptoms, they returned with greater intensity three weeks later.

Upon examination, doctors noted a generalized red rash, swollen lymph nodes (lymphadenopathy), and a high body temperature (39.0 °C). Blood tests revealed elevated white blood cell count with increased eosinophils and atypical lymphocytes. Further investigations, including a CT scan and FDG-PET-CT, revealed lung abnormalities and increased activity in the lymph nodes.

Key findings in this case included:

Erythroderma (widespread red rash)
Lymphadenopathy (swollen lymph nodes)
Eosinophilia (elevated eosinophil count)
Elevated levels of soluble interleukin-2 receptor
Reactivation of human herpes virus 6 (HHV-6)

Interestingly, standard allergy tests for levofloxacin (drug-induced lymphocyte stimulation test and patch testing) came back negative. Despite these negative results, the patient was diagnosed with DRESS/DIHS based on her symptoms and established diagnostic criteria, further supported by clinical scoring systems. Levofloxacin was stopped, and supportive treatment was initiated, leading to the remission of her symptoms. She experienced no relapse in the following year.

Levofloxacin and DRESS/DIHS: What You Need to Know

This case highlights the challenges of diagnosing DRESS/DIHS, especially when it is triggered by levofloxacin and occurs in patients with underlying autoimmune conditions. While allergy tests may be negative, clinicians should maintain a high index of suspicion based on clinical presentation and diagnostic criteria.

DRESS/DIHS is often misdiagnosed due to overlap with other conditions. The RegiSCAR and Kardaun's scoring systems aid in diagnosis. DRESS/DIHS can mimic other conditions, making diagnosis difficult. Negative allergy tests do not rule out DRESS/DIHS.

If you experience fever, rash, swollen lymph nodes, or other unusual symptoms after taking levofloxacin, seek immediate medical attention. Awareness of this potential adverse reaction is crucial for prompt diagnosis and management, ultimately leading to better outcomes.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

Everything You Need To Know

What exactly is DRESS/DIHS?

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as Drug-Induced Hypersensitivity Syndrome (DIHS), is a severe and potentially life-threatening reaction to medications. It's characterized by a combination of symptoms including fever, skin rash (erythroderma), internal organ involvement, and an increase in eosinophils (eosinophilia), which are a type of white blood cell. The significance lies in its severity and the potential for multi-organ failure. Because of the involvement of multiple organs, the implications are significant and require prompt diagnosis and management to prevent serious complications.

What is the role of Levofloxacin in this context?

Levofloxacin is a common antibiotic prescribed for various bacterial infections. The importance in this context stems from its potential to trigger DRESS/DIHS. It is a medication with the risk of side effects, as illustrated in the case study, where the patient developed DRESS/DIHS after taking the drug. If you are prescribed Levofloxacin it is important to be aware of potential side effects and to report any unusual symptoms to your healthcare provider immediately to help prevent serious complications.

Why are pre-existing autoimmune conditions relevant?

The case study presented involved a 77-year-old woman with a history of systemic scleroderma (SSc), rheumatoid arthritis (RA), and Sjogren's syndrome (SjS). These are autoimmune conditions. This means the immune system attacks the body's own tissues. The relevance of these conditions in this context is significant, as individuals with pre-existing autoimmune conditions are at a higher risk of developing DRESS/DIHS when exposed to certain medications, like Levofloxacin. The implication is that healthcare providers should be particularly vigilant when prescribing Levofloxacin to patients with these conditions, and patients should be aware of the increased risk.

What are the main symptoms of DRESS/DIHS?

The symptoms of DRESS/DIHS include fever, a widespread red rash (erythroderma), swollen lymph nodes (lymphadenopathy), and elevated levels of eosinophils (eosinophilia) in the blood. Internal organs can also be involved. The article highlights a patient with these symptoms following Levofloxacin treatment. Understanding these symptoms is critical for early diagnosis and intervention. The implications are that early recognition of these symptoms can lead to early diagnosis, which can help to prevent severe outcomes.

How is DRESS/DIHS diagnosed, and what are the challenges?

The diagnostic process for DRESS/DIHS can be challenging because symptoms can overlap with other conditions, and standard allergy tests might come back negative. In the case study, despite negative allergy tests, the diagnosis of DRESS/DIHS was made based on the patient's symptoms, established diagnostic criteria, and clinical scoring systems. Clinicians must rely on a comprehensive evaluation of the patient's symptoms and medical history. The significance of this approach is that it ensures proper and timely diagnosis, even in the absence of positive allergy tests. The implications are that clinicians must maintain a high index of suspicion and not solely rely on allergy tests, especially in the presence of specific clinical indicators, such as the symptoms of DRESS/DIHS.