Erythema is redness of the skin. It is caused by problems with the capillaries in the affected area. It can be associated with a wide range of medical issues, including chronic and acute conditions, trauma, inflammation, infection, and some genetic conditions. Commonly it is a symptom of an underlying medical issue and it can be an easily spotted warning sign because most people notice the change in skin color.
Many cases of erythema take the form of erythema multiforme, which is caused by allergies and some types of viral infections. Another example is erythema nodosum, in which fat cells under the skin become inflamed and red nodules develop. Erythema toxicum is a version seen in some newborn babies, characterized by a distinctive rash which resolves on its own in most cases. Radiation exposure, exposure to the sun, and exposure to infrared radiation can all cause erythema as well.
When a patient presents with erythema, the first step is to determine what is causing the redness. If the patient is experiencing immediate discomfort, medications may be provided to address symptoms like itching and soreness. Diagnostic procedures can include blood work, a physical examination, an interview with the patient, and a review of the patient's history. Once the cause is determined, the doctor can start to provide treatments for the cause, which should resolve the reddened skin as well.
For example, if a patient has erythema because of a viral infection, antiviral drugs can be provided to treat the infection. Conversely, if inflammation is the cause, steroids may be applied to mitigate the immune response which is causing the inflammation. There may be cases in which erythema is recurrent, a common problem with allergies and some autoimmune disorders, in which case the skin may become permanently discolored as a result of damage to the underlying capillaries.
Red skin in and of itself is not necessarily harmful, but it can be a sign of a serious underlying medical problem. If someone notices a rapid change in skin color, it is advisable to discuss with it with a doctor. The doctor can evaluate the situation to determine whether or not additional action should be taken. It is especially important to be alert to changes in skin color or texture for people who work in environments where high levels of radiation are present. This includes people exposed to infrared radiation, such as the heat from a laptop, which can cause erythema if the laptop is routinely used on someone's lap.
Erythema multiforme:
Fatigue, fever, itching (before lesions appear)
Sudden outbreak of spots, bumps, and lesions (usually on knees, elbows, palms, hands, and feet)
Target lesions (spots surrounded by rings of normal and red skin, looking like a target)
Erythema infectiosum (caused by a virus and known as fifth disease) -- rash on face and arms lasting about 2 weeks
Erythema nodosum:
Fatigue, flu like symptoms (before lesions appear)
Clusters of nodules (small round masses) and lesions on shins, forearms, thighs, and trunk
Red, painful lesions become soft and bluish, and fade to yellow and brown
Joint pain
Arthritis
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), the most severe forms of erythema multiforme, have a different set of symptoms. Target lesions on the trunk, hacking cough, fever, and blisters around the mouth, eyes, nostrils, and anal and vaginal areas are the key symptoms of SJS. A person with TEN will have symptoms of SJS that worsen to include peeling and detachment of the skin, pus like infections, fluid loss, and even death.
The nodules of erythema nodosum tend to go away by themselves and often do not need any treatment. However, they may be very tender or painful and certain treatments may be suggested to help relieve these symptoms.
So, treatments may include:
Painkiller medication. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used to help relieve pain. Sometimes stronger painkillers are needed.
Bedrest and keeping your legs raised above the level of your heart may help with pain relief.
Wearing firm, supportive bandages or stockings on your legs is another option. You can ask your doctor to advise about this.
Cool wet compresses over the nodules may also help to relieve pain.
Potassium iodide. In some people with erythema nodosum, this liquid taken by mouth may help relieve the pain in the nodules and also the joint pains. It is not certain exactly how this works and it is not effective in everyone.
Steroids. Steroids tablets are sometimes used provided erythema nodosum is not thought to have been triggered by an infection or a cancer. Steroids work by reducing inflammation. However, most of the time steroid treatment is not needed.
If an underlying trigger for erythema nodosum has been found, this may need to be treated. The treatment depends on the trigger.