5 Skin Disorders You Might Mistake for Hives

A heat rash can cause raised, red bumps on your skin that look similar to hives. While a heat rash and hives both have red, raised welts that itch, the bumps on the skin from a heat rash are usually smaller than hives and look more like small pimples.

Heat rash develops when blocked pores (sweat ducts) trap perspiration under your skin. Symptoms range from superficial blisters to deep, red lumps. Some forms of heat rash feel prickly or intensely itchy.

Heat rash develops when your pores get blocked and trap sweat under your skin. In infants, whose sweat ducts aren't quite as fully developed as adults, heat rash mainly shows up on the neck, shoulders and chest. Adults usually get it in skin folds or where their clothes causes friction with the skin [source: Mayo Clinic].

Most cases of heat rash will disappear in a couple of days if you air dry the skin, loosen and remove clothing and keep the temperature controlled whenever possible. If none of these work, you can apply calamine lotion or hydrocortisone cream to calm the rash, but you'll want to avoid other types of lotions or ointments because they can act as an irritant on the sensitive skin [source: WebMD].

Contact dermatitis is an itchy rash caused by direct contact with something your body is allergic to, including soaps, cosmetics, fragrances, jewelry or plants. Its symptoms include red bumps that could be confused as hives. The biggest difference between hives and contact dermatitis is hives manifest on several areas of the skin, but the rash from contact dermatitis pops up only on the area exposed to the allergen. Contact dermatitis generally lasts two to four weeks, and usually resolves itself without medication.

But you can treat it if necessary. Your doctor can give you oral corticosteroids to reduce inflammation, antihistamines to relieve itching or antibiotics to fight a bacterial infection. They also can give you topical cream or ointment to help soothe the rash [source: Mayo Clinic].

Rosacea, like hives, is a common skin condition. It causes redness and visible blood vessels, as well as small, red, pus-filled bumps, in your face. It's a chronic skin condition, which means these symptoms can flare up for weeks then go away.

Before the onset of rosacea, you may begin to notice that you blush easily and the redness continues across your face. When rosacea is inflamed, the small, red bumps crop up on the skin [source: National Rosacea Society]. Unlike hives, though, which can affect different parts of the body, rosacea is limited to the face.

The cause of rosacea is unknown, but it may have roots in hereditary factors as well as environmental ones. That said, there are certain things that aggravate the condition, such as exercise, consuming hot foods or alcohol, or exposure to sunlight, heat or stress [source: Mayo Clinic].

There is no complete treatment for rosacea, but there are topical and oral medications that have been known to help lessen its severity, including those that specifically target the blood vessels and meds that control the pimples of mild rosacea [source: Mayo Clinic]. Antibiotics may also help keep inflammation and redness down.

Atopic dermatitis, the most common type of eczema, looks a lot like hives. It causes red patches of itchy skin, small, raised bumps and cracked skin. It often shows up behind the knees, around ankles, wrists, face, neck and the upper chest area, and it can even affect the area around your eyes, including the eyelids. Unlike hives, though, eczema never really goes away.

Although the exact cause of eczema is unknown, it's thought to be linked with dry and irritated skin as well as an overactive immune system, which may cause the body to trigger allergic reactions when they're not necessary. It's also commonly linked with Staphylococcus bacteria, which can increase the severity of the symptoms. The symptoms can also be worsened by stress, sweating, dry skin, low humidity, dust, cigarette smoke, foods and wool or man-made clothing.

Eczema might look like hives on the surface, but where treatment is concerned, it's completely different. Even though eczema has been associated with allergies, getting rid of allergens is rarely helpful to the condition. Treatment is limited to things that lessen the pain of eczema, including corticosteroid creams and antihistamines to relieve itching, oral corticosteroids to decrease inflammation, and immunomodulators, which work with the immune system to reduce flare-ups. Light therapy is also known to be effective in dealing with eczema because ultraviolet rays can slow the inflammatory process [source: WebMD].

Like hives and everything else on this list, pityriasis rosea begins with large, raised red patches of skin. Pityriasis rosea may also come with a headache, fever, sore throat and stuffy nose. At the outset, pityriasis rosea begins with a herald patch, often confused for both hives and ringworm. As it progresses, it spreads around the initial patch with small, scaly spots resembling a pine tree [source: American Osteopathic College of Dermatology].

The cause of pityriasis rosea is unknown. No bacteria, fungus or virus has been attributed to its onset. It is possible that certain types of herpes may play a role, but no definitive cause has been found.

Generally, pityriasis rosea will go away on its own in four to six weeks, but in certain cases, a doctor may treat the rash. Certain antiviral medications are known to reduce the duration by a couple of weeks, but usually oral antihistamines and steroid creams are prescribed to help counter the itching.