Heat Rash Vs. Eczema

Our Zest dermatologists see many cases of heat rash and eczema. They are often asked how to tell the difference between the two conditions. It’s important to be able to differentiate between them as they require different treatments. 

We’ve put together this guide highlighting the key differences between heat rash and eczema. Learn about their causes, symptoms, treatments, and how to support your skin’s health.

What Is Heat Rash?

As its name implies, heat rash typically happens in hot or humid conditions. However, it can also occur in cold environments if you are overdressed and sweating. People who are bedbound or use a wheelchair can also develop heat rash on the areas of their skin that are in frequent contact with the bed or wheelchair. Babies are also at higher risk of developing heat rash as their sweat ducts aren’t fully developed.

Causes of Heat Rash

Heat rash develops when your sweat ducts become blocked when you are hot and sweating. Instead of the sweat being able to evaporate from your skin’s surface, it leaks into the lower layers of your skin. The collection of sweat under your skin’s surface causes red, itchy bumps to form. 

Common causes can include:

• Being in hot and humid environments
• Excessive sweating during physical activities
• Wearing tight or non-breathable clothing
• Overdressing in cold environments
• Being bedbound or requiring a wheelchair
• Having a high fever
• Occlusive or heavy topicals

Symptoms of Heat Rash

The most common symptoms of heat rash are red bumps or blisters and mild swelling. The rash typically appears on areas of the body prone to sweating, such as the neck, chest, back, and skin folds. However, the exact symptoms can vary depending on which layer of skin the sweat accumulates in.

Here’s a breakdown of the three main types of heat rash, or miliaria, and their symptoms: 

• Miliaria crystallina: This is the mildest form of heat rash, where sweat gets trapped just under the outer (epidermis) layer of the skin, leading to tiny, clear blisters that can break easily with slight pressure. 
• Miliaria rubra (prickly heat): This type occurs when sweat becomes trapped deeper in the skin, causing red bumps that feel itchy or prickly.
• Miliaria profunda: This more severe but rare form happens when sweat leaks into the deeper (dermis) layers of the skin, resulting in larger, firm bumps that can be painful.

The symptoms of heat rash can vary in intensity and may be more common in infants and young children due to their still-developing sweat ducts. 

Heat Rash Treatment

The most important step you can take in managing your heat rash is cooling your skin and reducing further sweating. 

Here are several strategies that can help:

• Move to a cooler environment: Try to get in an air-conditioned space or shaded area to help lower your body temperature.
• Wear loose-fitting, breathable clothing: When going out into the heat, wear loose, lightweight fabrics like cotton that allow air circulation. 
• Keep the skin dry: Regularly pat your skin dry if you are sweating excessively.
• Avoid heavy creams or ointments: These can block your sweat ducts further.

Most of the time, a heat rash resolves on its own within 24 hours to several days. In more severe cases, you may need to apply a corticosteroid cream to reduce inflammation, and in rare cases, an antibiotic cream may be necessary. 

If your symptoms persist or worsen, it’s a good idea to get the advice of a healthcare professional for further evaluation. 

What Is Eczema?

Eczema, also known as atopic dermatitis, is a chronic skin condition. It causes dry, itchy, and inflamed skin. While it’s not contagious, it is a disruption of the skin barrier that can be caused by genetics, immune system response, or environmental factors. 

Eczema is especially common among children but can affect individuals of all ages and can cause significant discomfort.  

Causes of Eczema

Medical experts are still researching the exact cause of eczema. However, they have come to believe it’s linked to a combination of genetic and environmental factors. 

If you have a family history of eczema or asthma, such as your mother, father, or sibling, you are more susceptible to having eczema. 

Things in your environment may also trigger an eczema flare-up. Common triggers include:

• Allergens such as pollen, pet dander, or dust mites
• Irritants like soaps, detergents, and certain fabrics
• Stress
• Changes in temperature or humidity 

These factors can compromise your skin's ability to act as a barrier, leading to moisture loss and increased sensitivity.

Symptoms of Eczema

Eczema has several symptoms, which may vary among individuals. Common signs include:

• Itching: Often intense, itching can worsen at night and may lead to scratching, which further irritates the skin.
• Dry, sensitive skin: Affected areas may appear rough, scaly, or thickened.
• Red or brownish-gray patches: These can occur anywhere but are commonly found on the hands, feet, ankles, wrists, neck, upper chest, eyelids, and in the bends of elbows and knees.
• Small, raised bumps: These may leak fluid and crust over when scratched.
• Swelling: Inflammation can cause the skin to become swollen and sensitive.

Eczema Treatment Options

While there's currently no cure for eczema, there are treatments that can help you relieve systems and reduce flare-ups. 

• Moisturize regularly: Keep your skin hydrated by applying a mild, fragrance-free cream or ointment right after bathing. 
• Apply topical corticosteroids: These anti-inflammatory creams or ointments can reduce redness and itching during a flare-up.
• Avoid triggers: Identify what may trigger your eczema and do your best to avoid those things. 
• Use gentle skin care products: Opt for mild, fragrance-free soaps and detergents to reduce irritation.
• Manage stress: Learning ways to manage your stress may help reduce stress-induced flare-ups.

If you are experiencing frequent or severe eczema flare-ups, it’s important to see a healthcare provider for a professional assessment and treatment plan.

Heat Rash vs. Eczema: Key Differences

Here is a breakdown of the key differences between heat rash and eczema.

Comparison of Symptoms

Here is a comparison chart of symptoms.

Triggers and Causes

Compare the different triggers and causes of heat rash and eczema. 

Treatment Approaches

See the differences in the treatment approaches.

Prevention Tips for Both Conditions

You can adopt several skincare routines to help minimize your risk of developing a heat rash or eczema flare-up. 

• Maintain skin hydration: Apply fragrance-free, hypoallergenic moisturizers to keep your skin hydrated and strengthen its barrier function if you have eczema. If you are prone to heat rash, avoid overhydrating your skin and using occlusive topicals. 
• Choose appropriate clothing: Wear loose-fitting, breathable fabrics like cotton to allow air circulation and reduce skin irritation. Tight or synthetic clothing can trap sweat, increasing the risk of heat rash and exacerbating eczema symptoms.
• Bathe mindfully: Use lukewarm water for bathing rather than hot, and opt for gentle cleansers. After bathing, gently pat your skin dry and immediately apply a moisturizer to lock in moisture.
  Manage environmental factors: Keep your living spaces cool and well-ventilated to prevent excessive sweating. Use fans or air conditioning to help maintain a comfortable temperature and reduce the likelihood of heat rash. Cool mist humidifier 
• Identify and avoid triggers: If you suffer from eczema, it's crucial to recognize and steer clear of specific triggers, such as certain soaps, detergents, or allergens that can provoke flare-ups.

While you can manage most cases of heat rash and eczema with home care, it’s important to seek medical attention in certain circumstances.

• Signs of infection: If your rash increases in redness, swelling, warmth, or develops pus or odor, these may be indications of an infection requiring medical treatment.
• Persistent or worsening symptoms: If your symptoms don’t improve with at-home care, get worse over time, or are severe, it's important to consult a healthcare provider for proper diagnosis and treatment.
• Uncertainty about the condition: If you're unsure whether your skin issue is heat rash, eczema, or another condition, seeking medical advice can ensure appropriate management and prevent complications.

Conclusion

Distinguishing between heat rash and eczema is essential for effective management and relief. 

While both conditions manifest as skin irritations, heat rash typically occurs from blocked sweat ducts in hot, humid environments and presents as small red bumps or blisters. In contrast, eczema is a chronic inflammatory condition, often linked to genetic and environmental factors, characterized by red, itchy, and sometimes scaly patches.

Accurate diagnosis is crucial, as treatment approaches differ significantly between the two conditions. 

For personalized care and expert guidance, consider consulting with the specialists at Zest Health. As a virtual dermatology clinic, Zest Health specializes in managing chronic skin conditions, including eczema. They offer value-based, clinically proven care with the convenience of next-day appointments and 24/7 messaging support.