Lab Tests and Eczema: What Your Results May Mean for Skin Health

Living with eczema means navigating daily struggles with itching, irritation, and unpredictable flare-ups that affect both physical comfort and emotional well-being. Managing a chronic condition with no clear triggers can feel isolating, overwhelming, and even embarrassing—but you're not alone.

Eczema, a type of dermatitis characterized by immune dysregulation, involves non-infectious skin inflammation caused by environmental factors and genetic sensitivity. This leads to fluid buildup between skin cells, weakening the skin barrier and increasing irritation and discomfort.

Lab tests can provide life-changing insights for people with eczema by ruling out similar conditions, identifying allergens through IgE testing, and measuring inflammation markers to guide treatment—especially in severe or complex cases. Understanding your lab results is key to transforming your eczema management.

This guide explains common lab results relevant to eczema and the next steps to consider.

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Why Lab Tests are Important for Eczema Management

Lab tests offer insights beyond physical exams: they can identify triggers, assess inflammation severity, and rule out conditions like infections or autoimmune disorders. 

They help guide treatment decisions by measuring markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), which assess the level of inflammation.

In more severe cases, blood work can uncover immune dysfunction or chronic inflammation requiring specialized care. These tests may also help identify triggers behind co-existing conditions like asthma or allergic rhinitis, contributing to a more comprehensive treatment plan.

And while eczema itself is not an autoimmune condition, research has shown a strong link between eczema and the development of autoimmune diseases, and blood tests may help identify early autoimmune tendencies, allowing for timely intervention.

Although lab tests don’t directly diagnose eczema (clinical diagnosis relies on patient history and physical examination), they provide deeper insights into underlying factors that help clinicians develop more targeted and effective treatment plans.

Common Lab Tests for Eczema

Dermatologists may order the following tests to identify factors triggering eczema flare-ups:

Total IgE (Immunoglobulin E) Test

This test measures IgE levels, which are linked to allergic tendencies. Elevated IgE in eczema patients suggests an overactive immune response to triggers like dust mites, pollen, or foods. 

However, as high IgE can also appear in other conditions (e.g., parasitic infections or autoimmune diseases), results must be considered alongside the patient’s symptoms and medical history.

Specific IgE (Allergen-Specific Test)

RAST (radioallergosorbent test) and ImmunoCAP tests measure IgE antibodies to specific allergens, identifying sensitivities to triggers like pollen, dust mites, or foods (e.g., eggs, peanuts). 

A positive result highlights allergen sensitivities, guiding trigger management. However, results should be interpreted in context of the patient’s symptoms and history, as results can be inaccurate as much as 60% of the time. 

Complete Blood Count (CBC)

A CBC measures various blood cells and provides a health overview. For eczema patients, elevated white blood cells can indicate infection or inflammation, while eosinophil levels suggest an allergic response. Other CBC parameters, like hemoglobin and platelets, offer insight into overall health and help rule out underlying conditions affecting skin health, such as anemia.

Eosinophil Count

Eosinophils are white blood cells involved in allergic responses and inflammation. Elevated eosinophils in eczema often indicate a stronger allergic reaction, worsening inflammation, itching, and skin dysfunction. High eosinophils can also be seen in asthma. 

This test helps assess the severity of the allergic response and guides further allergen testing or treatment adjustments.

C-Reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR)

These tests measure inflammation in the body. CRP reflects acute inflammation, while ESR indicates chronic, long-term inflammation. 

CRP is a protein produced by the liver in response to inflammation, typically rising during acute inflammatory conditions such as infections or flare-ups in chronic diseases like eczema.

ESR measures how quickly red blood cells settle in a test tube, with faster sedimentation rates indicating higher levels of inflammation in the body.

Elevated CRP and ESR levels in eczema suggest significant inflammation that may require more aggressive treatment or monitoring. These markers guide decisions on adjusting treatment to manage the condition effectively.

Understanding Your Lab Results: What the Numbers Mean

Understanding your lab results is essential for managing eczema effectively. This section explains key concepts like reference ranges, what high or low results mean, and how to engage in meaningful discussions with your healthcare provider.

Understanding Reference Ranges

A reference range shows expected levels of a lab marker based on the general population, varying by age, gender, and the lab. But what’s normal for a child may differ for an adult, and health factors can shift your personal range, so always have your results interpreted by a professional.

Compare your values to the reference range, but discuss them with your provider to understand their meaning in the context of your symptoms and history.

High vs. Low Results: What They Indicate

It is important to understand what high and low results may indicate:

Total IgE (Immunoglobulin E)

High Total IgE: this indicates an exaggerated immune response, which is common in eczema and other allergic conditions (e.g., asthma, hay fever) or parasitic infections. Higher IgE levels often suggest that the body is reacting strongly to allergens like dust mites, pollen, or food, and may indicate an increased risk of asthma.

High IgE levels are more commonly seen in extrinsic eczema, which is associated with external allergens like pollen or food, and is often linked to skin barrier dysfunction. 

Low Total IgE: generally, low IgE levels are less concerning, but they can indicate that allergies are less likely to be driving symptoms. 

However, a low IgE result does not rule out eczema or atopic tendencies. Intrinsic eczema involves normal or low IgE levels, lacks clear allergen associations, and tends to have a relatively intact skin barrier. 

Specific IgE (Allergen-Specific Test)

High Specific IgE: a positive result for specific allergens (e.g., dust mites, pollen, peanuts) suggests that these substances trigger an allergic response in your body, likely contributing to eczema flares. High levels help guide treatment strategies, although false positives are not uncommon.

Low Specific IgE: a low result suggests less likelihood of sensitivity to that particular allergen. However, a negative result doesn’t entirely rule out allergens as triggers, especially if symptoms are present.

Eosinophils

High Eosinophils: elevated eosinophils are typically seen in allergic reactions and inflammation, often indicating a strong immune response to allergens in eczema. High levels may suggest the need for more aggressive anti-inflammatory treatments.

‍Low Eosinophils: low levels of eosinophils are generally normal, indicating that the body is not experiencing significant allergic or inflammatory reactions at the time of the test.

C-Reactive Protein (CRP)

High CRP: CRP is a marker for inflammation in the body. High levels indicate acute inflammation, potentially signaling an active flare-up of eczema or another inflammatory condition, or a new infection. 

Low CRP: low or normal CRP suggests there is little to no active inflammation in the body, which is typically expected when eczema is well controlled or in remission.

Erythrocyte Sedimentation Rate (ESR)

High ESR: a high ESR suggests chronic inflammation. While this marker increases more gradually than CRP, elevated levels can point to long-term inflammatory conditions, such as eczema, that require ongoing management.

Low ESR: low or normal ESR values are usually indicative of little or no inflammation, suggesting stable eczema or a lack of chronic inflammatory conditions.

It’s important to remember that lab results should not be interpreted in isolation. Trends over time, rather than a single result, provide a clearer picture of what’s happening in the body. Monitoring these trends helps guide adjustments to treatment and care strategies.

Discussing Results with Your Doctor

When reviewing lab results for eczema management, ask your healthcare provider:

• What do these results mean for my condition?

• How do they relate to my symptoms and overall health?

• Are there trends over time we should note?

• Should my treatment plan change based on these results?

Discuss how lab results fit with your symptoms and medical history for a clearer picture. Don't hesitate to ask for explanations of complex terms or clarifications to ensure you're fully informed and able to make the best decisions for your care.

Using Lab Results to Guide Treatment Decisions

Lab results can help tailor your eczema treatment plan and guide decisions on lifestyle changes, medications, and products. Ultimately, lab results should empower you to make targeted changes for better eczema management.

Allergen-Specific Results

If tests show sensitivities (e.g., to pollen or foods), you can adjust your environment and diet to minimize exposure by using allergen-proof bedding, using hypoallergenic soaps and detergents or eliminating trigger foods.

Inflammation Markers

Elevated CRP or ESR may require stronger treatments like steroids or biologics. Anti-inflammatory lifestyle changes (e.g., omega-3-rich diet, stress management) may help in milder cases.

Further Testing

If results are unclear or suggest immune dysfunction, more testing or a specialist referral might be needed.

Understanding Variability in Lab Results

Lab results can fluctuate due to factors like recent infections, medications, or stress, and these variations are normal. Rather than focusing on a single test result, it’s important to track trends over time and see how your numbers align with your symptoms. 

Repeat testing helps confirm trends or validate findings, so talk to your doctor about when retesting or additional tests might be needed to get the clearest picture of your condition.

The Limitations of Lab Tests in Eczema

While lab tests can provide essential information, it’s important to keep their limitations in mind. 

Eczema is Primarily a Clinical Diagnosis

Diagnosing eczema relies on symptoms like itchy, red skin and rashes. 

Test results are most valuable when combined with a clinical assessment, taking the patient’s full history and symptoms into account. Lab results help refine care but don’t provide a complete diagnosis.

Non-Specific Results

Tests like total IgE can indicate elevated allergic responses but aren’t specific to eczema. High eosinophils, CRP, and ESR can also be seen in other conditions besides eczema, so results must be interpreted carefully by doctors to avoid misdiagnosis or unnecessary treatment.

False Positives and Negatives

Specific IgE tests can help identify allergens but are not always reliable. False positives might suggest allergens that don’t cause symptoms, while false negatives can miss real triggers. 

Doctors need to weigh test results against clinical observations for accurate diagnosis.

Comprehensive Use in Complex Cases

Blood tests are most useful for severe or unclear cases of eczema, where a deeper understanding of immune function is needed. Routine eczema cases can often be managed based on clinical symptoms without extensive testing.

Importance of Tracking Trends

Lab results can fluctuate due to factors like infections, stress, or medication. Tracking trends over time, rather than relying on one-time results, is the best way to guide treatment decisions. 

Lab Results Are a Doorway to a More Holistic Approach

Lab tests are just one tool in managing eczema and should not be relied on in isolation for treatment decisions. A holistic approach takes into account not only lab results but also a patient's symptoms, lifestyle, environmental factors, and medical history. 

This comprehensive view helps doctors develop more personalized, effective treatment plans that address the root causes and triggers of eczema, rather than just treating the symptoms.

While lab tests provide useful insights, they should always be combined with clinical assessments to create an effective, personalized treatment plan for eczema.

When to Seek a Second Opinion

If you're dealing with conflicting lab results, an unclear diagnosis, or persistent symptoms despite treatment, it may be time to seek a second opinion. Specialists like dermatologists and allergists can provide additional insights, offering a fresh perspective on your condition and treatment options. 

If you feel your current treatment isn’t working, or if further testing is needed, ask for a referral to another specialist or consider exploring alternative therapies that might better address your unique needs.

A Functional Medicine Perspective on Lab Testing for Eczema

Functional medicine practitioners focus on uncovering the root causes of eczema, such as immune dysregulation and genetics, while also considering how diet, lifestyle, and environmental factors contribute to flare-ups. 

By addressing these underlying triggers, functional medicine can provide personalized solutions to help manage and improve eczema through targeted diet and lifestyle changes.

A functional medicine practitioner may consider additional testing for: 

Digestion, The Microbiome and Diet

Food sensitivities and poor gut health can trigger or worsen eczema. Functional medicine practitioners explore dietary triggers and promote anti-inflammatory diets to support gut health, proper digestion, and a healthy microbiome.

The gut microbiome plays a critical role in regulating inflammation and immune responses, which directly impacts the skin microbiome through the gut-skin axis; a functional medicine practitioner may consider testing the gut microbiome in eczema patients when signs of gut imbalance or persistent inflammation suggest that addressing gut health could help improve skin symptoms.

Functional medicine practitioners might consider comprehensive digestive and microbiome testing, as well as food sensitivity testing, for further insight into gut health. 

Toxin and Mold Exposure

Environmental toxins and mold can overload the body’s detox systems, worsening immune dysregulation and aggravating eczema. Detox strategies and reducing toxin exposure may alleviate symptoms.

Test panels are available to assess for toxin or mold exposure. 

Hormones

Hormonal imbalances, especially involving cortisol and thyroid hormones, can trigger flare-ups.  For example, hypothyroidism may worsen eczema flare ups.

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which controls cortisol production, is also linked to eczema flare-ups, especially under stress.

Thyroid testing that includes thyroid antibodies, and a diurnal cortisol test that includes the cortisol awakening response (CAR), may be considered. 

A Deep Dive Into Genetics

Genetic factors can affect skin barrier function and immune responses. Genetic testing can guide personalized treatments based on a person’s specific genetic vulnerabilities.

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Key Takeaways

• Lab tests help identify triggers, assess inflammation, and rule out similar conditions, guiding personalized eczema treatments for more effective management.

• Patients should actively discuss lab results with their providers to better understand how they relate to symptoms and adjust treatment plans accordingly.

• Using lab results alongside clinical assessments empowers patients to make targeted decisions, leading to improved eczema control and overall skin health.