If you’ve been using Dupixent to treat what you thought was severe eczema, there’s a troubling possibility you need to be aware of: the condition you’re treating might not be eczema at all. In some cases, a rare form of skin cancer named cutaneous T-cell lymphoma (CTCL) can look nearly identical to eczema, leading to months or even years of misdiagnosis.
The problem becomes more complicated when Dupixent enters the picture. Because the drug works by suppressing immune system activity and reducing inflammation, it can actually mask the early warning signs of CTCL or change how the lymphoma presents on your skin.
For Dupixent patients, understanding the difference between eczema and CTCL is potentially life-changing. This guide will help you recognize the subtle signs that might indicate misdiagnosis, explain why CTCL is so often confused with eczema, and clarify what steps you should take if you’re concerned about your diagnosis.
The emerging research linking Dupixent to delayed CTCL detection
A 2025 systematic review published in Dermatitis analyzed 35 case reports, case series, and retrospective patient reviews. Although each study looked slightly different, the authors noted a striking throughline: patients being treated with Dupixent for what was believed to be severe eczema were later found to have CTCL after their disease worsened, changed appearance, or failed to respond as expected.
The review proposed two primary explanations:
- Misdiagnosis at the very beginning: CTCL in its earliest stages often looks exactly like chronic eczema — dry, itchy, red patches; scattered plaques; and inflammation that waxes and wanes. Many of the patients in the reviewed cases had longstanding symptoms that seemed consistent with dermatitis, leading clinicians to escalate therapy before considering a biopsy.
- Immune pathway changes influencing how CTCL behaves: Dupixent works by blocking IL-4 and IL-13 pathways. While these pathways drive eczema flares, they also interact with T-cell activity. The review authors raised the possibility that suppressing certain inflammatory signals might unintentionally alter the visibility or presentation of T-cell cancers, allowing them to progress beneath the surface.
The authors emphasized that this does not mean Dupixent causes CTCL. Instead, it underscores how Dupixent can complicate the clinical picture, and why persistent or changing lesions should prompt a much earlier biopsy than many patients receive.
What Dupixent patients should look for in their own history
Many people who develop CTCL after or during Dupixent use only recognize the pattern when they look back at how their skin changed over time. Reviewing your own timeline can help determine whether your experience resembles what researchers and clinicians are now seeing in Dupixent T-cell lymphoma cases.
Timeline clues
Certain timing patterns appear repeatedly in published case reports and patient histories:
- Symptoms that started before Dupixent, improved briefly, then worsened again: This “improve, then decline” pattern is common when early CTCL responds to reduced inflammation but continues growing under the surface.
- New or spreading lesions after beginning Dupixent: Many patients describe rashes that expanded to new areas of the body, even while inflammation decreased in other spots.
- Rashes that stopped responding to treatments that used to help: Steroids, moisturizers, or prior therapies may lose effectiveness as CTCL evolves.
- Gradual enlargement or thickening of plaques over months or years: Slow but steady progression is characteristic of early-stage CTCL.
These shifts don’t confirm CTCL on their own, but they can signal that a closer review of your medical history was warranted earlier.
Medical record clues
Medical records often show red flags that were easy to miss at the time but become clearer in hindsight. These clues help establish whether a patient’s experience fits the misdiagnosis pattern that has become central to Dupixent T-cell lymphoma lawsuits:
- Dermatology notes describing “eczema that never fully clears,” even while on advanced therapies like Dupixent.
- Comments about atypical lesion patterns, such as sharp borders, unusual distribution, or plaques that behave differently than standard eczema.
- Biopsy recommendations that were postponed or never pursued. Delayed tissue sampling is common in cases where CTCL initially resembles dermatitis.
- Pathology reports eventually confirming CTCL after years of dermatitis treatment.
How attorneys evaluate Dupixent T-cell lymphoma cases
Attorneys reviewing Dupixent T-cell lymphoma claims start by examining whether the person’s medical experience fits the well-documented diagnostic challenges surrounding CTCL. The combination of timing, documentation, and symptom evolution plays a key role.
Several types of evidence can help confirm that a case aligns with recognized Dupixent T-cell lymphoma patterns:
- Biopsy confirming CTCL, Mycosis Fungoides, or Sézary Syndrome: This is the single most important diagnostic element.
- Documented Dupixent use before or during significant symptom changes: Prescription history and pharmacy logs help establish the timeline.
- Repeated eczema treatment without a biopsy: This shows how CTCL may have been masked or mistaken for dermatitis over time.
- Skin disease that worsened while on Dupixent: Especially when new plaques developed or lesions deepened.
- Imaging or lab findings showing disease progression: This includes lymph node involvement or abnormal blood results.
If your symptoms or diagnosis resemble the patterns discussed above, a free case review can help clarify your options. Our team at Slater & Zurz can examine your dermatology records, biopsy reports, and Dupixent treatment history to determine whether your experience aligns with the emerging CTCL research. We’ll also walk you through what a Dupixent lymphoma lawsuit may involve and help outline the next steps at your pace.
For a more detailed overview of how these cases work, check out this guide. Otherwise, start with your free case review by calling us at 330-762-0700 today.
Written by Robert Horton
Rob, a partner at Slater & Zurz, brings over a decade of experience advocating for the injured. His exceptional negotiation skills have consistently secured favorable outcomes for clients in motor vehicle accidents, dog bite incidents, and slip-and-fall cases.
