Several allergic skin conditions can cause symptoms like itchiness, irritation, and skin color changes. For example, these are symptoms of both atopic dermatitis and chronic hives. Although they’re separate conditions with different causes and appearances, they both cause skin inflammation and itchiness. Since they can cause similar symptoms, you might wonder whether there’s any connection between these two conditions.

Although atopic dermatitis and chronic hives tend to look different, they share some common features. Beyond sharing symptoms, both conditions involve the immune system, can be triggered by similar factors, and share some treatments. All of this can make it easy to confuse atopic dermatitis and chronic hives.

Here, we’ll explore five ways that atopic dermatitis and chronic hives are connected.

Atopic Dermatitis vs. Chronic Hives

These two conditions have distinct differences and similarities. Understanding their underlying mechanisms and how they affect the skin can help in managing these conditions.

Atopic Dermatitis

Atopic dermatitis is a type of eczema — a skin condition that develops from inflammation. It most often begins during early childhood, but it can also develop in adults. Although some children grow out of atopic dermatitis, for others it’s an ongoing condition that continues to affect them into adulthood. Atopic dermatitis is the most common of the seven types of eczema.

Atopic dermatitis usually appears as a rash of dry or cracked skin. Affected skin may be itchy and look swollen, bumpy, or crusty. Depending on skin tone, the rash can appear red, purple, gray, or brown. For many people, rashes will come and go (flare) over time.

Chronic Hives

Hives are raised wheals (welts) or bumps that develop on the skin and are often itchy. Hives are defined as chronic if they happen two or more times a week for at least six weeks. Some people with chronic hives may have them for years before they resolve. Chronic hives are reported to affect around 4.5 percent of people at some point in their lives and are more common in women aged 30 to 50 years. Healthcare providers refer to hives as urticaria.

There are two kinds of chronic hives:

• Chronic inducible urticaria (CIndU) — Hives that flare up after you’ve been exposed to a certain trigger, such as cold, heat, or pressure.
• Chronic spontaneous urticaria (CSU) — Hives that flare up due to an unknown cause or that are related to an autoimmune disease like lupus. This type is also called chronic idiopathic urticaria.

How Atopic Dermatitis and Chronic Hives Are Connected

Despite being separate conditions, atopic dermatitis and chronic hives can both cause skin to itch and change colors. The two chronic conditions also have several other things in common.

1. They Can Share Triggers

A trigger is something that causes symptoms to flare or worsen. For both conditions, flare-ups can be caused by many different triggers.

Often, an allergen or an irritant is responsible for flares ofatopic dermatitis. “Atopic” is a medical term used that describes a genetic tendency to develop allergic reactions. These reactions can happen in parts of the body that haven’t come into direct contact with an allergen. Triggers for atopic dermatitis can vary by person and can be hard to identify, especially if symptoms don’t begin right after exposure.

Common triggers of atopic dermatitis include:

• Environmental allergens, such as pollen, pet dander, and dust mites
• Cold
• Heat and humidity
• Stress
• Sweat
• Clothing made of scratchy materials, such as wool
• Household cleaning products like soaps and detergents
• Skin care products, especially those with added fragrance

Food allergens aren’t common triggers of atopic dermatitis in adults, but they can trigger eczema in young children.

While chronic hives rarely appear after exposure to an allergen — such as certain foods, medications, bee venom, or vaccines — they share many of the same physical and environmental triggers as atopic dermatitis. Chronic hives can also be triggered by hot and cold temperatures, pressure on the skin, sunlight, and exercise. However, most cases of chronic hives have no known trigger.

2. Immune System Dysfunction Plays a Role in Both

Your immune system is designed to be your defense against bacteria and other germs that can harm you. The skin serves as the immune system’s first line of defense. The cells that make up the skin — known as the skin barrier — help keep germs, allergens, and other invaders from entering the body.

But, sometimes, this barrier doesn’t function exactly as it should. This is the case for both people with atopic dermatitis and those with chronic hives.

In atopic dermatitis, the skin barrier is impaired and can’t provide adequate protection. Germs and irritants penetrate the faulty skin barrier and enter the body, prompting the immune system to release chemicals that cause inflammation. This, in turn, further weakens the skin barrier, leading to a vicious cycle of inflammation. When the skin fails to keep germs out, the immune system has trouble calming down due to their constant presence.

Chronic hives are thought to occur due to a similar immune response — mast cells (immune cells in the skin) react when they shouldn’t. When these cells are triggered, they release chemicals like histamine that cause inflammation. Often, this misfire is due to the immune system mistakenly attacking itself with antibodies it produces.

More research into CIndU, in particular, is needed. But, some evidence shows that the mast cells in people with CIndU are more easily triggered than in those without chronic hives.

3. Both Conditions Can Make You Itchy

In atopic dermatitis, skin barrier dysfunction leads to the release of chemicals called cytokines. Cytokines are in charge of managing inflammation in the immune system’s fight against invaders. When the immune system is triggered, the release of cytokines produces inflammation. This inflammation is what causes symptoms like itchy skin and painful rashes.

Although chronic hives also cause itchiness, the process is different. When mast cells are activated, they release histamine and other inflammatory chemicals. This makes blood vessels widen and leak fluid out into the skin. This fluid leak is what causes symptoms of hives like swollen welts, itchy skin, and redness. In some cases, swelling may occur in deeper layers of the skin, a condition that doctors call angioedema.

4. Both Are Linked to Allergic Conditions

Allergens are a common trigger of atopic dermatitis flares. The condition is also linked to allergies in other ways. People who have hay fever or other allergies have an increased risk of developing atopic dermatitis.

Meanwhile, having severe atopic dermatitis is a risk factor for developing other allergic conditions — specifically, food allergies, asthma, and hay fever. One theory to explain this connection is that a disrupted skin barrier increases sensitivity to allergen within the skin. This sensitivity can lead to inflammation in the skin and other parts of the body that have similar structures, such as the respiratory and digestive tracts.

Chronic hives have also been linked to allergies and allergic diseases. In addition to medication and food allergies potentially being a trigger, having chronic hives can make you more likely to develop allergic conditions like atopic dermatitis, asthma, and hay fever.

This connection may stem from the fact that chronic hives and allergies both involve an overactive immune system. In both hives and allergies, the release of histamine from mast cells is what leads to symptoms like itchiness. However, it’s important to note that one condition doesn’t cause the other. Rather, people with chronic hives and those with allergies often share an overly reactive immune system.

5. They Have Some Treatments in Common

Since atopic dermatitis and chronic hives both relate to immune dysfunction and cause similar symptoms, they share some treatment options. To manage itchiness and improve quality of life, antihistamines are often recommended for people with chronic hives and may also be used for atopic dermatitis. Avoiding any known triggers is also key for both conditions.

Management of chronic hives focuses on preventing mast cells from releasing histamine and blocking the chemical’s effects in the body while treatment for atopic dermatitis focuses on restoring the skin barrier. A primary care or dermatology provider may recommend people with atopic dermatitis apply cold compresses, ointments, lotions, or creams to help restore moisture to your dry skin. You’ll need to avoid scratching, rubbing, or irritating your rash in any way to allow your damaged skin to heal.

In addition to antihistamines, topical corticosteroid (steroid) creams may be used to help reduce inflammation in people with atopic dermatitis. For those with a severe rash, biologic medications or immunosuppressants (drugs that weaken the immune system) may be prescribed. Biologics are also used to treat chronic hives that don’t respond to antihistamines.

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