What is an itchy rash?
An itchy rash is an inflammatory reaction of the skin. An itchy rash is a symptom of a wide variety of mild to serious diseases, disorders and conditions.
Itchy rashes differ in severity, frequency and duration depending on the underlying cause. Itchy rashes can appear as blotchy or tiny spots or occur in a large, solid continuous area. In some cases, an itchy rash may include scaling or flaking of skin cells, and blisters that can ooze clear-colored fluid.
An itchy rash can indicate a relatively mild and easily treated condition, such as irritant contact dermatitis or ringworm (a fungal infection of the skin). An itchy rash can also result from viral infections, autoimmune disorders, and insect bites. Persistent scratching can worsen itchy rash symptoms and leave the affected skin susceptible to contamination and infection.
An itchy rash or hives accompanied by difficulty breathing and swelling of the tongue or face may be due to a life-threatening allergic reaction called anaphylaxis. Seek immediate medical care (call 911) if you, or someone you are with, have any of these symptoms. Seek prompt medical care if you do not have life-threatening symptoms but your rash is not improving or interferes with your daily life.
What other symptoms might occur with an itchy rash?
An itchy rash can occur by itself or with other symptoms that affect the skin and possibly other areas of the body. Symptoms vary depending on the underlying disease, disorder or condition. For example, you may have flu-like symptoms if the itchy rash is due to infection or inflammation. Anxiety and irritability may be caused by constant itching due to the rash.
Skin symptoms that may occur along with an itchy rash
Itchy rash may occur with other skin-related symptoms including:
Bleeding from broken skin
Flaking or scaling of the skin
Oozing of discharge from the rash or surrounding skin
Redness, irritation or inflammation
Swelling or puffiness around the rash
Other symptoms that may occur along with an itchy rash
An itchy rash may occur with symptoms related to body systems other than the skin including:
Irritability in infants and children
Red or dry eyes
Stress, anxiety or depression
Serious symptoms that might indicate a life-threatening condition
In some cases, an itchy rash may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (c all 911) if you, or someone you are with, have any of these symptoms:
What causes an itchy rash?
Itchy rashes can be caused by a wide variety of diseases and conditions, such as infection, inflammation, allergic reaction, parasite and insect bites, and autoimmune processes. For example, a small localized itchy rash may be caused by contact dermatitis due to contact with an irritant or allergen. A generalized itchy rash that covers large parts of the body may be due to a viral infection or scabies (mite infestation that leads to a widespread immune response). More serious causes of an itchy rash include a severe allergic reaction with anaphylaxis, a life-threatening condition associated with hives and difficulty breathing.
One way to help determine the cause of a rash is to keep a diary noting when it flares up.
Infectious causes of an itchy rash
An itchy rash may be caused by an infection including:
Bacterial infection, such as from streptococcal or staphylococcal bacteria
Pityriasis rosea (suspected viral origin)
Autoimmune and inflammatory causes of an itchy rash
An itchy rash can be caused by an autoimmune and inflammatory disorder including:
Systemic lupus erythematosus
Psoriasis (chronic skin disorder involving overproduction of skin cells)
Allergic causes of an itchy rash
An itchy rash can be caused by an allergic reaction including:
Allergic contact dermatitis caused by an allergy to such substances as detergents, latex, or an insect bite
Eczema (atopic dermatitis)
Irritant contact dermatitis, such as diaper rash
Poison ivy, poison oak, or poison sumac
Scabies (allergic reaction to mite bites)
Parasites, insects and arachnids that cause an itchy rash
An itchy rash can be due to insects, parasites or arachnids that bite the skin or burrow in the skin including:
Mosquito bites (mosquitoes also carry parasitic diseases)
Life-threatening causes of an itchy rash
In some cases, an itchy rash may be a symptom of an immediately life-threatening allergic reaction called an anaphylactic reaction, which causes swelling, tightening and closing of the airways that can rapidly lead to death if not treated immediately.
Questions for diagnosing the cause of an itchy rash
To diagnose the underlying cause of an itchy rash, your doctor or licensed health care practitioner will ask you several questions related to your symptoms. You can best help your health care practitioner in diagnosing the underlying cause of your itchy rash by providing complete answers to these questions:
Describe the itchy rash. Where is it? What does it look like? When did it appear?
What other symptoms are you having?
Have you been in recent contact with any unusual or new substances or environments, such as poison ivy, new medications or food, or travelling outside the United States?
Provide your full medical history, including all medical conditions, surgeries and treatments, family history, and a complete list of the medications and dietary supplements that you take.
In some cases, an itchy rash can lead to complications, especially if there is severe itching and scratching that leads to breakdown of the skin. Scratching can introduce bacteria or fungus into the layers of skin, resulting in infections. Complications include:
Cellulitis, an infection of the skin and surrounding tissues caused by a growing bacterial or fungal infection
MRSA methicillin resistant Staphylococcus aureus infection
Open sores and lesions
Permanent change in skin texture, scarring
Permanent skin discoloration
Complications of underlying causes of an itchy rash can also occur. You can reduce the risk of complications of an itchy rash and its underlying causes by following the treatment plan you and your health care provider develop specifically for you.