A rash is an area of swollen, irritated skin that manifests in different patterns and varying shades of red, purple or brown. Some rashes are caused by allergic reactions to the environment, food or medications, while others appear because of a skin disorder or underlying disease or infection. Some clear up on their own, but others are chronic and require treatment to control symptoms.
Hives or urticaria is a very common type of itchy, red or skin-colored rash that sometimes burns or stings. It usually appears as welts, bumps or plaques called wheals on the skin. They can appear on any part of the body, move locations, change shape or disappear and reappear.
Chronic hives appear almost daily and may last months, while acute hives may last only a few days. This rash is typically caused by an allergy to a drug or food but other causes include stress or infections.Hives usually goes away on its own. But serious cases that last longer may require a shot or oral medication. Rarely, hives can cause swelling in the airways, making it difficult to breathe.
Common hives triggers include:
- Antibiotics such as penicillin and NSAIDs such as aspirin and ibuprofen
- Bites or stings from insects
- Blood transfusions
- Certain foods, especially eggs, peanuts, shellfish and nuts
- Certain plants
- Exposure to latex
- Infections caused by bacteria, such as urinary tract infections and strep throat
- Infections caused by viruses such as infectious mononucleosis, hepatitis and the common cold
- Pet dander
- Pressure, heat, cold, sun exposure, exercise or physical stimuli
Contact dermatitis happens when the skin encounters an irritant such as poison oak or poison ivy, a household chemical, hand sanitizers, soaps or certain metals such as nickel or gold. Sometimes, the reaction might occur after sun exposure.
Symptoms of contact dermatitis include:
- Blisters or bumps that may or may not be filled with clear fluid
- Irritated, red and swollen skin
- Skin that feels hot or tender
The rash can appear hours or days after contact with the irritant. Washing the skin with soap and water immediately after contact with the irritant may help. Doctors may prescribe creams or oral medication to help the skin heal and control itching.
Allergists may be able to perform a patch test to figure out what is causing the irritation. The patch contains common irritants such as hair dye, rubber or fragrances. Patients wear the patch for about two days, then the doctor checks for results.
Eczema, also called atopic dermatitis, is a chronic long-lasting disease that manifests as a rash with redness, swelling, cracking and extreme itchiness. Usually it appears on the arms, legs, and cheeks. It can affect anyone at any age, but usually begins in childhood.
The rash comes and goes, and sometimes it disappears completely. When the rash is active, it’s called a flare. It’s a common disease, and about 18 million American adults have the disease, according to the National Eczema Association.
Symptoms of atopic dermatitis include:
- Scaly, dry skin
- Rash that appears on the cheeks, legs and/or arms
- Flares come with open, weepy or crusty sores in severe cases
Treatments include medications, skin care to avoid dry skin, and phototherapy — a type of therapy that uses ultraviolet light to control rashes.
Psoriasis is an autoimmune condition that manifests as a scaly, flaky, itchy, burning rash. People with psoriasis have skin cells that grow too fast. This causes the cells to pile up on the skin’s surface, causing redness and inflammation.
It typically affects the scalp, knees and elbows, but it can appear in any location according to the National Psoriasis Foundation — even the genitals and fingernails. It’s also associated with other diseases such as depression, heart disease and diabetes.
Common symptoms of psoriasis include thick, raised patches of skin called plaques. These patches can be light pink or deep red and are covered with a layer of silvery, dry skin called scales. The way it looks and specific symptoms vary depending on the type of psoriasis.
Treatment includes oral medications, topical ointments and creams and phototherapy.
Lupus is a long-term autoimmune disease that causes the immune system to attack healthy cells and tissues. It affects internal organs, joints and skin. People with lupus often have a butterfly-shaped rash on the nose and cheeks. There are four kinds of lupus: systemic lupus erythematosus (SLE), cutaneous lupus, drug-induced lupus and neonatal lupus. SLE is the most common kind.
Lupus can affect anyone, but it most often occurs in women ages 15 to 44. Because lupus is an autoimmune disease, it affects the entire body.
Symptoms of lupus include:
- Butterfly-shaped rash on cheeks and nose
- Chest pain when taking deep breaths
- Hair loss
- Joint pain and swelling
- Mild fevers
- Sensitivity to sunlight
- Sores in the nose or mouth
Some skin disorders may resemble rashes, but don’t have the typical symptoms of other rashes.
Vitiligo may resemble a rash because it causes patches of skin discoloration, but it’s not a rash. It is a condition that causes skin to lose color. It causes milky-white patches of skin on the face, hands, feet and arms. People with vitiligo may also have hair that runs white on their head, beard, eyelashes and eyebrows.
Rosacea is a skin condition that may also affect the eyes. It causes pimples and redness on the face and is common in fair-skinned people. Other symptoms include a swollen nose, small red lines under the skin, frequent flushing, thick skin, and itchy dry eyes.
When to Seek Treatment
Most rashes are not life threatening, but some symptoms may signal a more serious condition. The American Academy of Dermatology recommends that people seek medical help if they have any of the following symptoms.
- The rash covers the entire body
- You have signs of infection, such as swelling, yellow or green fluid, crusting, pain, warmth or a red streak coming from the rash
- You have pain in the rash
- Blisters in the rash turn into open sores, especially if it’s around the mouth, eyes or genitals
- The rash comes with a fever, a potential sign of an allergic reaction or infection (shingles, measles, scarlet fever)
- The rash appears suddenly and spreads rapidly