Itching, swelling, and red and white welts are all signs you may have hives — or chronic idiopathic hives, if the welts appear consistently for six weeks or more and have no known cause. While any skin rash might seem to you to be an allergic reaction or hives, the reality is there are numerous skin disorders that can be mistaken for chronic hives.
How to Tell if It’s Chronic Hives
If you notice a persistent, itchy skin rash, seeing a dermatologist is a good first step toward confirming a diagnosis and finding relief. “Giving a complete medical history and undergoing a physical exam are the best ways to determine what’s causing the rash or hives, and if there is a more serious skin disorder behind it,” explains Joseph L. Jorizzo, MD, a professor of dermatology at Weill Cornell Medical College in New York City and Wake Forest Baptist Health University School of Medicine in Winston-Salem, North Carolina.
Hives can appear anywhere on the body, and they can change shape, travel, and disappear and reappear within short periods of time. Hives can also appear as bumps or swollen red or skin-colored welts or “wheals” with clear edges and a red center that when pressed turns white. While the cause of chronic hives is typically unknown, some common triggers include certain foods, medications, insect bites, pet dander, viral or bacterial infections, and reactions to physical stimuli like temperature and sun exposure.
5 Skin Disorders Often Confused With Hives
Hives can be mistaken for other skin disorders, such as:
Heat rash. This skin condition occurs in hot, humid weather and can be aggravated by clothing that causes friction or blocks sweat ducts. The rash of fluid-filled blisters and bumps can be itchy and sensitive. Cases of heat rash can range from mild to severe, where the bumps contain pus or affect the deeper layer of the skin. Unlike chronic hives, heat rash typically clears on its own and can be treated by cooling the skin and reducing sweating.
Contact dermatitis. This is a common condition in which something that touches the skin causes a red rash. The reaction may be caused by an allergy to an ingredient in makeup or a particular metal in jewelry, or by continuous contact with an irritant such as soap or bleach. But whereas hives cause an itchy reaction, most people who experience contact dermatitis feel more of a stinging or burning sensation, and the reaction appears only where the skin has come in contact with the trigger.
Rosacea.Unlike hives, which can occur anywhere on the body, rosacea is limited to the face and is characterized by redness on the cheeks, nose, chin, or forehead. Small, visible blood vessels and pimple-like bumps on the face, as well as watery or irritated eyes, are other common symptoms. Rosacea cannot be cured, but it can be controlled with the use of certain medications.
Eczema.The symptoms of eczema generally vary from person to person and can be found all over the body. Causing red, inflamed, dry, scaly, and intensely itchy skin, eczema can be difficult to distinguish from hives. As with chronic hives, the exact cause of eczema is unknown, but it's thought to be linked with dry, irritated skin and an overactive immune system. The treatment is different from that for hives, which is why it's important to have a doctor diagnose the skin disorder you have and recommend proper treatment.
Pityriasis rosea. This common skin disease causes a splotchy red rash that appears on the body and typically lasts around six to eight weeks, although sometimes much longer. Unlike chronic hives, pityriasis rosea usually disappears on its own without treatment.
More Serious Skin Problems
The main feature distinguishing chronic hives from more serious skin disorders is whether the welts are filled with fluid. If the red bumps are itchy, inflamed, and filled with fluid, the condition is most likely hives. If they’re hard and filled with other material besides fluid, and if after a skin test the lesions have a brownish color, there’s most likely an underlying problem.
"A lesion that looks like a hive can be circled,” says Dr. Jorizzo. “If the individual lesion lasts longer than 24 hours, more serious urticarial lesions such as urticarial vasculitis or an urticarial lesion of bullous pemphigoid must be excluded by biopsy."
So if you experience hives or hivelike symptoms, it’s important to see your doctor to determine the source, if possible, and discuss the appropriate treatment.
