A rash is a change in the skin that can result in bumpy, blotchy, or scaly patches. Many people have had an itchy rash at some point in their lives. Many are harmless and will go away on their own, but others may be more persistent due to underlying causes or conditions.
Many different factors can cause an itchy rash, including:
- an allergic reaction to foods, medications, or objects, such as nickel earrings
- touching or exposure to environmental allergens
- diseases such as chickenpox
- chronic conditions, such as psoriasis
- infections such as ringworm
- infestations such as scabies
Sometimes, an itchy rash will improve without complicated treatment or prescription medication. However, a rash can be an early indication or warning sign of a more serious long-term health concern, which a person should address.
It is important to take itchy rashes seriously, particularly if they are long lasting and of unknown origin. Here are eight of the more common examples of itchy rashes.
Roughly 20% of infants and children have eczema, but it only affects 1 in 50 adults. Eczema, or atopic dermatitis, causes an inflamed, irritated, and itchy rash.
Some other conditions often linked with eczema include:
- hay fever
- food allergies
The American Academy of Allergy, Asthma & Immunology report that about 50% of the individuals with severe eczema have a common genetic disturbance.
Conventional treatments for eczema include steroidal creams for reducing inflammation and moisturizers for protecting the skin.
Doctors will prescribe antibiotics if the skin becomes infected.
2. Skin allergy
A range of everyday products and plants from rubber gloves to poison ivy contain different allergies that can cause an itchy rash in people who are sensitive to them.
The medical term for this response is allergic contact dermatitis. According to the National Institutes of Health NIH, nickel, which inexpensive earrings for pierced ears often contain, is the most common cause of allergic contact dermatitis.
Symptoms can develop within a day or two after exposure but may take weeks to go away.
Calamine lotions and oatmeal baths might help control itching.
Severe forms, including a rash on the face or an uncomfortable rash that will not go away, may require prescription topical or oral steroids. Avoiding known triggers is the best way to prevent future episodes.
Many doctors and skin specialists consider psoriasis to be an autoimmune inflammatory disorder that disrupts the normal cycle of skin cells. A haywire immune system causes white blood cells to wreak havoc in the skin, resulting in red, raised, scaly plaques.
Around 2% of people living in the United States have psoriasis. It is a genetic disease that runs in families, so it is not contagious. This means that a person cannot contract psoriasis from coming into contact with someone who has it.
The location and appearance of plaques depend on the type of psoriasis.
With plaque psoriasis, which affects 90% of people with psoriasis, pink or red plaques develop in symmetrical patterns on the elbows, knees, and near the hairline. These plaques usually have a layer of white dead skin cells.
Another common type of psoriasis is guttate psoriasis. People with guttate psoriasis develop multiple little raised, red papules and plaques.
More severe forms of psoriasis, such as erythrodermic psoriasis, which affects a large portion of the body, or pustular psoriasis, which causes pus-filled blisters, are less common. Psoriasis can also cause pitting and other damage to fingernails and toenails.
In addition to the physical and social discomfort that an itchy psoriasis rash can cause, it can also lead to other complications, including psoriatic arthritis. This affects up to 30% of people with psoriasis and carries an increased risk for cardiovascular disease, diabetes, inflammatory bowel disease, and metabolic syndrome.
Treatment depends on the severity of an individual’s psoriasis. Options range from topical skin treatments to light therapy to systemic medications that target the immune system.
Hives, or urticaria, are a kind of itchy rash triggered by the body’s release of histamine in response to:
- eating certain foods, including shellfish, peanuts, and tree nuts
- taking medications that someone has an allergy to, such as sulfa drugs and penicillin
- insect bites
- intense physical activity
The American College of Allergy, Asthma, & Immunology report that roughly 20% of people will experience hives at some point in their lives.
In most cases, hives get better within a few days. However, some people have hives for months at a time.
Allergies rarely cause these long lasting or chronic cases of hives. Antihistamines can usually control itching and discomfort in acute cases.