Considerations

Causes

A simple rash is called dermatitis, meaning inflammation of the skin. Contact dermatitis is caused by things your skin touches, such as:

• Chemicals in elastic, latex, and rubber products
• Cosmetics, soaps, and detergents
• Dyes and other chemicals in clothing
• Poison ivy, oak, or sumac

Seborrheic dermatitis is a rash that appears in patches of redness and scaling around the eyebrows, eyelids, mouth, nose, the trunk, and behind the ears. If it happens on your scalp, it is called dandruff in adults and cradle cap in infants.

Age, stress, fatigue, weather extremes, oily skin, infrequent shampooing, and alcohol-based lotions aggravate this harmless but bothersome condition.

Other common causes of a rash include:

• Eczema (atopic dermatitis) -- tends to happen in people with allergies or asthma. The rash is generally red, itchy, and scaly.
• Psoriasis -- tends to occur as red, scaly, itchy patches over joints and along the scalp. Fingernails may be affected.
• Impetigo -- common in children, this infection is from bacteria that live in the top layers of the skin. Appears as red sores that turn into blisters, ooze, then crust over.
• Shingles -- a painful blistered skin condition caused by the same virus as chickenpox. The virus can lie dormant in your body for many years and re-emerge as shingles.
• Childhood illnesses such as chicken pox, measles, roseola, rubella, hand-foot-mouth disease, fifth disease, and scarlet fever.
• Medications and insect bites or stings.

Many medical conditions can cause a rash as well. For example:

• Lupus erythematosus
• Rheumatoid arthritis, especially the juvenile type
• Kawasaki disease

Home Care

Most simple rashes will improve with gentle skin care and avoiding irritating substances. Follow these general guidelines:

• Avoid scrubbing your skin.
• Use as little soap as possible. Use gentle cleansers instead.
• Avoid applying cosmetic lotions or ointments directly on the rash.
• Use warm (not hot) water for cleaning. Pat dry, don't rub.
• Eliminate any newly added cosmetics or lotions.
• Leave the affected area exposed to the air as much as possible.
• Try calamine medicated lotion for poison ivy, oak, or sumac as well as other types of contact dermatitis.

Hydrocortisone cream (1%) is available without a prescription and may soothe many rashes. If you have eczema, apply moisturizers over your skin. Try oatmeal bath products, available at drugstores, to relieve symptoms of eczema, psoriasis, or shingles.

When to Contact a Medical Professional

Call 911 if:

• You are short of breath, your throat is tight, or your face is swollen
• Your child has a purple rash that looks like a bruise

Call your health care provider if:

• You have joint pain, fever, or a sore throat
• You have streaks of redness, swelling, or very tender areas as these may indicate an infection
• You are taking a new medication -- DO NOT change or stop any of your medications without talking to your doctor
• You may have a tick bite
• Home treatment doesn't work, or your symptoms get worse

What to Expect at Your Office Visit

Your health care provider will perform a physical examination and ask questions about your medical history and symptoms. Questions may include:

• When did the rash begin?
• What parts of your body are affected?
• Does anything make the rash better? Worse?
• Have you used any new soaps, detergents, lotions, or cosmetics recently?
• Have you been in any wooded areas recently?
• Have you had any change in your medications?
• Have you noticed a tick or insect bite?
• Have you eaten anything unusual of late?
• Do you have any other symptoms like itching or scaling?
• What are your underlying medical problems? Do you have, for example, asthma or allergies?

Tests may include:

• Allergy testing
• Blood tests
• Skin biopsy
• Skin scrapings

Depending on the cause of your rash, treatments may include medicated creams or lotions, medications taken by mouth, or skin surgery.

Many primary care providers are comfortable dealing with common rashes, but for more complicated skin disorders, a referral to a dermatologist may be necessary.

Alternative Names

Skin redness or inflammation; Skin lesion; Rubor; Skin rash; Erythema

References

Anderson BE, Marks JG Jr. Plant-induced dermatitis. In: Auerbach PS, ed. Wilderness Medicine. 5th ed. Philadelphia, Pa:Mosby Elsevier;2007:chap 57.

Cydulka RK, Garber B. Dermatologic presentations. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 118.

Armstrong CA. Examination of the skin and approach to diagnosing skin diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 444.

Werth VP. Principles of therapy of skin diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 445.

Updated: 4/7/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.