The Erythema: A Mysterious Disease


It is a condition of the skin characterized by redness or rash of it. There are many types of erythema, including sensitive, multiform, and knotty photo.

Photo sensitivity is caused by a reaction to sunlight and tends to occur when something, such as an infection or medication, increases your sensitivity to ultraviolet radiation.

The multiforme is characterized by flat spots or other skin lesions. It is usually caused by a reaction to medications, infections (especially herpes simplex virus), or disease.

The knotty is a variant of erythema that is accompanied by very sensitive lesions, which are usually located on the legs below the knees, and can be caused by certain medications or diseases.

What causes it?

More than half of the cases of this mysterious disease still do not know the exact cause. In other cases, a variety of causes can result in erythema.

Erythema multiforme occurs by:

Infection, mainly of the simple herpes virus. Medications, such as penicillin and sulfonamides; anticonvulsant medications; Non-steroidal anti-inflammatory drugs (NSAIDs)

Erythema nodosum can occur due to:

  • Infections, including mononucleosis
  • Connective tissue disorders, such as lupus.
  • Pregnancy.
  • Ulcerative colitis
  • Behcet’s disease
  • Crohn’s disease.
  • Medications, such as birth control pills

Who is most at risk?

Men are at a higher risk than women with erythema multiforme. Women are more at risk than men from getting erythema nodosum.

  • Excessive or frequent sun exposure increases the risk of erythema multiforme.
  • People between 20 to 30 years of age are at greater risk of erythema nodosum.
  • People with a family history of skin diseases are more likely to develop any form of erythema multiforme or erythema nodosum.

What are your symptoms?

The symptoms of erythema multiforme are:

  • Fatigue, fever and pruritus (before the lesions appear).
  • Sudden outbreak of spots, bumps and injuries (usually appear on the knees, elbows, palms, hands and feet).
  • Erythema infeccioso (caused by a virus), rashes on the face and arms that last approximately 2 weeks.

Among the symptoms of erythema nodosum we have:

  • Fatigue, flu-like symptoms (before the lesions appear).
  • Clusters of nodules (small and round masses) and lesions on the forearms, thighs and trunk.
  • Painful, red lesions that turn soft and bluish, and fade to yellow and brown.
  • Joint pains
  • Arthritis.

What are the treatment options?


It is necessary to treat underlying diseases and avoid known triggers (certain medications, for example). It is also important to avoid the sun when taking certain medications.

Treatment plan

Your doctor will treat any underlying disease, avoiding any medication that may contribute to worsening symptoms and taking steps to control your current symptoms.

Mild cases may not require treatment. Bed rest and medications may be necessary for more severe cases.

Therapies with medicines.

  • Antihistamines for itching.
  • Antibiotics In case you have an infection, although research suggests that many cases of erythema can be resolved without antibiotics.
  • Antiviral medications such as Acyclovir, in case you have the virus.
  • Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs).
  • The compresses are a solution that is used to soothe skin conditions, in particular blisters.
  • Corticosteroids, applied to the skin (topically); Corticosteroids can also be taken orally to reduce the symptoms of erythema nodosum.
  • The intravenous immunoglobulin.
  • Photo-modulation therapy, the use of a light-emitting diode to accelerate the elimination of erythema.