A rash behind the ear may occur due to a variety of different medical conditions. Certain viral infections and autoimmune diseases may cause a rash behind the ear in both children and adults. While some causes, such as contact dermatitis, are not concerning, other causes, including rubella, may be more serious.
In this article, we look at some of the causes of a rash behind the ear, as well as the other symptoms that they may produce and how to treat them.
Contact dermatitis is an allergic reaction to a particular substance.
If an allergy-inducing substance comes into contact with the skin behind the ear, a rash can form.
Allergens that may cause contact dermatitis behind the ears include:
- other hair care products
For example, hair dye products contain an ingredient called paraphenylenediamine (PPD), which is a common contact allergen.
Contact dermatitis causes itchiness, dryness, and flaking of the skin that came into contact with the allergen.
A doctor will diagnose contact dermatitis by first taking the person’s medical history and carrying out a physical examination. Relevant medical history includes hobbies, medications, and use of fragrances and perfumes.
Then, the doctor will assess the person’s symptoms and check the results of a patch test.
In some cases, they may need to perform a biopsy to confirm the diagnosis.
When possible, avoiding the substance that triggers the rash or reaction is the best method of treatment.
A doctor may sometimes recommend topical or oral corticosteroids to reduce inflammation and itching.
Over-the-counter and prescription oral antihistamines may also help relieve itchiness.
Some people may find that applying cold or wet soaks to the skin soothes it and relieves itching. They can also apply moisturizers.
People with scalp psoriasis have discolored plaques of thickened skin that can appear behind the ears.
The plaques can become itchy and flake, resulting in a dandruff-like appearance.
Other symptoms of scalp psoriasis include:
- silvery-white scales
- dry scales
- dry, cracked scalp
- hair loss
Doctors can generally diagnose psoriasis by examining the lesions on the skin.
People with scalp psoriasis can use topical treatments, as they typically have mild involvement of the rest of the skin.
Some people may require systemic drugs if they also have large lesions on their body.
The topical agents that people may use to treat scalp psoriasis include:
- coal tar
- vitamin D analogs
- other various forms of shampoos with oils and other ingredients that aim to soothe and reduce the symptoms
However, the hair on the head can make these treatments difficult to apply. As a result, some people may stop using the products.
Localized ultraviolet B therapy is an alternative to topical medications but is a more expensive treatment that is not widely available.
Systemic drugs remain off-label for the treatment of scalp psoriasis. These drugs include:
- cyclosporin A
- biological therapy
Intertrigo can occur at any age, but young people and older adults have a higher chance of developing it. People with a weakened immune system are also at higher risk. Some babies may develop intertrigo behind their ears due to drooling when they sleep.
Intertrigo can occur when skin rubs against another area of skin in a part of the body that is subject to moisture and friction. As a result, the skin can become inflamed.
Other bodily secretions, such as saliva, sweat, urine, and feces, can irritate the skin and cause intertrigo.
Symptoms of intertrigo include:
- flushed skin
- a burning sensation
Doctors need to inspect the skin to identify the type of rash.
A careful examination may reveal secondary bacterial or fungal infections that may require different treatments.
First-line treatment options include:
- zinc oxide ointments
- talcum powder
- aluminum sulfate
- calcium acetate solution
- low potency corticosteroids
If the doctor diagnoses a secondary bacterial or fungal infection, the person may require antibacterial or antifungal treatment, such as:
- topical erythromycin
- topical clindamycin
- Whitfield’s ointment
- topical mupirocin
Rubella, also known as German measles, is a rare viral infection that affects children and young adults who are not immune.
However, in pregnant women, if rubella develops within the first 10 weeks of pregnancy, it can cause severe complications. These include pregnancy loss, fetal death, and severe congenital abnormalities.
The CDC state that 25–50% of those who contract rubella will be asymptomatic.
However, if symptoms do appear, they will typically differ slightly between children and adults.
The CDC note that children tend to experience a rash that appears on the face and then spreads to the body. The rash will last about 3 days.
Other symptoms that can appear 1–5 days before the rash include:
Adults with rubella typically experience a mild illness and have a sore throat, low grade fever, and a rash that first appears on the face before spreading to the rest of the body.
A person is contagious from 8 days before to 8 days after the rash appears.
As the symptoms of rubella are sometimes mild and nonspecific, doctors may sometimes find it challenging to diagnose basd on a physical examination.
Serology testing for rubella is more accurate.
With serology testing, doctors check for rubella-specific immunoglobulin M antibodies. These antibodies are detectable about 4 days after the rash appears.
The incidence of rubella has decreased significantly in many countries due to the introduction of a vaccine in 1969.
Rubella has no cure, which is why prompt intervention is necessary if symptoms develop.
Management typically involves supportive treatments, such as fluids, antipyretics, or nonsteroidal anti-inflammatory drugs for fever and aches. Some people may receive a combination of these.
The virus rubeola causes measles.
People can get the measles from other people via airborne particles.
The measles rash occurs behind the ears and along the hairline. It can descend to the face, trunk, arms, and legs.
According to the CDC, measles can be dangerous.
Children under the age of 5 years and adults over the age of 20 years are more likely to experience complications. These can range from diarrhea to pneumonia and encephalitis. Encephalitis is the inflammation of the brain.
Doctors describe three stages of the measles infection: prodromal, eruptive, and convalescent.
During the prodromal stage, people may experience:
- high fever
- inflammation of the nasal passages
- inflammation of the inside of the eyelids
- dry cough
In the eruptive stage, the person develops a rash behind the ear and along the hairline, which can spread to the face, trunk, and extremities.
In the last stage, the rash starts to disappear in the same order in which it appeared.
Fever and general malaise may resolve 2–3 days after the rash starts.
To diagnose measles, doctors look at the person’s symptoms, the spread of measles in the community, and the results of laboratory tests.
Blood tests can check for specific immunoglobulins and can isolate the virus that caused the infection.
Getting vaccinated can help prevent the spread of measles.
According to the CDC, children should get the vaccination at 12–15 months of age and get a booster shot at 4–6 years.
Although no cure for the measles exists, doctors may provide medicine to help with the fever.
In infants, a rash behind the ear can occur due to:
Another name for cradle cap is seborrheic dermatitis.
Cradle cap appears in areas of the body with plenty of sweat glands, including the scalp.
Sometimes, babies may develop cradle cap behind their ears.
In infants, cradle cap may cause the following symptoms:
- yellow crust on the skin
- flushed skin with white or yellow flakes
Cradle cap does not typically agitate the baby, but parents or caregivers should check the scalp for signs of infections.
Doctors will carefully examine the scalp of an infant with suspected cradle cap because many other skin conditions may appear similar.
Infants with cradle cap will present with thick, greasy scales that do not cause itchiness.
Other conditions that may resemble cradle cap include:
- fungal infections
According to the United Kingdom’s National Health Service (NHS), a parent or caregiver can:
- wash the infant’s hair regularly using baby shampoo
- gently brush the scalp with a soft brush
- apply baby oil, petroleum jelly, or vegetable oil to the affected areas overnight and wash them in the morning using baby shampoo
A person should avoid using soap, peanut oil, and adult shampoos. They should also avoid picking the crusts as this may cause infection.
Many different medical conditions can cause a rash. People with unexplained rashes should speak with a doctor or other healthcare provider.
Additional symptoms, such as fever, malaise, or nausea, may be associated with an infection and require immediate medical attention and treatment.
Repeated scratching that exposes the skin can cause a rash to become infected. Anyone who develops an infection from a rash should see a doctor.
Different skin conditions, such as contact dermatitis and psoriasis, can cause rashes to appear behind the ears.
People who contract infections such as rubella and measles may present with a rash.
In infants, a rash behind the ear is more likely to be due to cradle cap or intertrigo.
Any rash that occurs along with fever and other systemic symptoms, does not resolve on its own in a few days, or causes significant distress requires medical attention.