Dyshidrotic Eczema or Fungal Infection? The Misdiagnosis Epidemic
The medical literature does not support a definitive cause for dyshidrotic eczema; many consider it a questionable or imprecise diagnosis. Hypotheses for its origin range from stress and food allergies to topical allergic reactions, but none have been conclusively proven. Diagnoses of dyshidrotic eczema in the dermatological community continue to increase year after year.
This is problematic, as dyshidrotic eczema presents with intense itching, vesicles, and fissuring on the fingers and palms — symptoms that closely mimic tinea manuum (fungal infection of the hand) and other cutaneous mycoses. In contrast, fungal conditions such as tinea manuum, tinea pedis, and candidiasis have well-established etiologies and can be cured with inexpensive and readily available antifungal treatments.
A reevaluation of cases labeled as dyshidrotic eczema may reveal that many are, in fact, misdiagnosed fungal infections — especially when symptoms persist or worsen with corticosteroid treatment. Multiple studies and case reports support this concern:
- In a study published in JAMA Dermatology, 10% of 120 patients diagnosed with pompholyx (dyshidrotic eczema) were found to have mycosis (fungal infection) as the underlying cause.
- A 2018 review in Mycoses emphasized that dermatophyte infections, particularly tinea incognito, are commonly misclassified as eczema due to atypical presentations exacerbated by corticosteroid use (Seebacher et al., 2018).
- A report in the Journal of Clinical and Aesthetic Dermatology noted that fungal infections are often overlooked because clinicians fail to perform potassium hydroxide (KOH) microscopy or fungal cultures, instead opting for visual diagnosis followed by topical steroids (Del Rosso, 2011).
These findings highlight the importance of considering fungal infections in the differential diagnosis of dyshidrotic eczema, particularly when standard treatments are ineffective. It can appear as though the intention is to keep the patient returning for unnecessary appointments and expensive medications.
A Case in Point: A Misdiagnosed 21-Year-Old Male
In a documented case involving a 21-year-old male, the patient was diagnosed with dyshidrotic eczema by a board-certified dermatologist in Michigan after presenting with blistering on the hands. On the first visit, the individual requested a culture or fungal test be performed. He was dismissed, and a 30-second diagnosis was given. The patient was released 10 minutes later and provided with several samples of corticosteroid creams and a prescription for an additional one. Over the course of two more monthly visits (three in total), he was prescribed varying strengths of corticosteroids with no lasting improvement. After months of discomfort and pain, partial relief came from an over-the-counter antifungal cream, suggesting an alternative etiology.
The turning point came when a KOH test, conducted in a private laboratory after discontinuing the corticosteroid creams, confirmed the presence of fungal hyphae under microscopic examination. Despite his academic background in biomedical sciences, the patient had trusted the medical diagnosis of a board-certified dermatologist until mycological evidence suggested otherwise. Unfortunately, by this point, the infection had significantly damaged his nail folds and hand skin barrier.
That patient? My youngest, 21-year-old son. For nearly a year, my son struggled with an aggressive rash on his hands — blistering, peeling, pervasive itchiness, and persistent irritation. He’d been diagnosed with dyshidrotic eczema and sent home with a handful of topical steroid cream tubes. Month after month, the treatment did nothing but mask the symptoms. The rash worsened. His cuticles began to recede, the skin on his fingers thickened, and his quality of life diminished as the use of his right hand, the most affected, became problematic. As a mother and a cosmetic chemist, something didn’t sit right with me from the beginning. The fact that his request for a proper test was dismissed at the first visit did not sit well with me.
He wasn’t just any patient. He’s my son, and we’re both scientists. He holds a degree in biomedical sciences from Oakland University, while I’ve been a cosmetic chemist for nearly 20 years. Despite his own training, and mine, he trusted the diagnosis and followed the standard treatment plan by his dermatologist. I had my doubts since the diagnosis was issued. The blistering, the way the skin responded, the pervasive itch — something about it triggered a memory. I had seen this before—on my own feet as a 12-year-old child while living abroad in Venezuela. In my case, it wasn’t misdiagnosed. I was provided with the correct diagnosis and proper medication and, in less than a month, my condition disappeared. But despite my own experience, he didn't trust me, and I didn't trust the dermatologist.
Are medical diagnostics better in other countries? Sometimes they are. Doctors there don’t get kickbacks for prescribing medications like they do in the US, and the diagnostics as well as treatments are intended to cure the condition, not just treat the symptoms, which is an unfortunately common practice in the US.
Tired of it all, we took matters into our own hands. At my skincare lab, we conducted a simple, well-documented, and valid 10-minute potassium hydroxide (KOH) test. Under the microscope, hyphae — the telltale branching structures of a fungal infection — were clearly visible. The diagnosis? Not dyshidrotic eczema. It was a fungal infection, plain and simple.
This experience isn’t isolated. Misdiagnosing fungal infections or dermatophyte infections as eczema is far more common than it should be.
Research shows that up to 30% of suspected cases of chronic hand or foot eczema may actually be tinea manuum or tinea pedis — a fungal infection of the hands or feet that mimics the symptoms of eczema almost identically (Liu et al., 2014; Seebacher et al., 2018).
Yet most doctors and dermatologists never conduct the 10-minute KOH test to confirm the diagnosis before prescribing potent corticosteroids.
Why? Several reasons: the most common, pharmaceutical incentives — some physicians may be incentivized to prescribe certain medications due to relationships with pharmaceutical companies; lack of knowledge — not all professionals in any field are truly competent; cockiness — after diagnosing one too many with a certain condition, they assume everyone with a similar condition suffers from the same disease; lack of professionalism — not taking patient’s concerns seriously and denying a simple test for a better outcome.
"Fungal infections of the skin can resemble many other common dermatoses, and misdiagnosis can lead to inappropriate treatment. A simple KOH preparation can distinguish these conditions in a matter of minutes, leading to accurate diagnosis and cure." (Gupta et al., 2003)
Topical corticosteroids may reduce inflammation and itchiness temporarily, but they don’t address the root cause. Worse, they can suppress local immune response, allowing fungal infections to proliferate unchecked. Over time, this not only delays proper treatment but also increases the risk of skin atrophy, hypopigmentation, and even systemic side effects.
The Myth of Dyshidrotic Eczema
The term "dyshidrotic eczema" is often used as a catch-all diagnosis for itchy, blistering eruptions on the hands, feet, and other parts of the body. However, recent literature questions whether this term represents a true disease entity or simply a placeholder for a spectrum of conditions — including undiagnosed fungal infections, contact dermatitis, or palmoplantar psoriasis.
A 2019 review by Nguyen and Tosti found that “in many cases, dyshidrotic eczema may overlap with or mask other dermatoses, including dermatophytoses, yet diagnostic confirmation is rarely pursued through microscopy or fungal culture.” (Nguyen & Tosti, Clinical Dermatology Review, 2019)
The Problem with Corticosteroids
Topical corticosteroids, while effective in controlling inflammation, suppress immune responses and allow fungal infections to proliferate unchecked. This misuse not only exacerbates fungal infection, but also leads to tinea incognito — an altered, less obvious form of fungal infection that is more difficult to diagnose and treat.
Prolonged or repeated steroid use is associated with skin atrophy, delayed healing, perioral dermatitis, and in some cases, systemic side effects including hormonal disruption and fertility complications (Foti et al., 2020).
Why Fungal Testing Should Be the Standard—But Is Too Often Ignored by Dermatologists
A KOH prep is a simple, low-cost diagnostic test that takes less than 10 minutes, involves minimal patient discomfort, and provides a definitive answer. A few skin scrapings dissolved in a potassium hydroxide solution can reveal the presence of fungal hyphae under a microscope in minutes. Yet in many clinical practices, especially dermatology, it is skipped entirely. According to a 2019 survey published in Dermatologic Therapy, fewer than 20% of U.S. dermatologists regularly perform in-office KOH exams, relying solely on a 1–2 minute clinical observation (Singh et al., 2019).
Considering that tinea infections account for nearly 25% of global dermatologic cases (WHO, 2017), misdiagnosis at this scale reflects a systemic issue rooted in diagnostic shortcuts and pharmaceutical dependency.
A Call for Awareness
This is why I’m sharing our story. As a mother, a scientist, and the founder of the only Italian skincare company manufacturing Italian products in the US, committed to integrity and efficacy, I believe the skincare and dermatological communities owe patients more than a two-second glance and a prescription pad. Millions may be misdiagnosed, enduring unnecessary treatment with potent topical steroids for a condition they don’t even have. Worse yet, they’re being deprived of a real cure — a proper antifungal diagnosis and the adequate course of treatment.
What Needs to Change
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Routine Fungal Testing: Any case of eczema should automatically prompt a KOH test or culture to rule out other underlying conditions.
- More Conservative Use of Steroids: Steroid creams should not be prescribed without ruling out fungal causes first.
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Patient Education: People deserve to know that their persistent rash might not be eczema at all.
The Hippocratic Oath, amongst its many foundational statements in modern medicine, reads:
- Beneficence: The obligation to act in the best interests of the patient and to benefit them.
- Non-maleficence: The principle of "first, do no harm," meaning physicians should avoid causing harm to patients.
- Maintaining Trust: The oath emphasizes the importance of maintaining trust between the physician and the patient.
With every misdiagnosis, these three important tenets of the Hippocratic Oath are eroded, leading to mistrust in the medical community.
Final Thoughts
Millions may be undergoing steroid therapy for a condition they do not have. This poses not only medical risks but also ethical concerns in dermatological care. Patients presenting with blistering, redness, and chronic irritation of the hands, feet, or anywhere should be screened for fungal infections via KOH or culture testing before initiating long-term corticosteroid treatment. Until this becomes standard practice, misdiagnoses will continue — delaying healing and compromising skin health.
Trust your instincts. Ask your doctor or dermatologist for a fungal test and don’t allow them to dismiss you. Our story is just one of many. But if it can prevent one more misdiagnosis, one more damaged hand, one more unnecessary round of steroids — it’s worth sharing.
