A-Z OF SKIN

Also known as … Superficial or Deep Gyrate Erythema, Erythema Perstans, Palpable Migrating Erythema

What is Erythema Annulare Centrifugum?

Erythema Annulare Centrifugum (EAC) refers to an annular (ring-shaped) erythematous (red) skin eruption that tends to spread outwards whilst clearing centrally.

The cause of EAC is unknown but it is probably due to a hypersensitivity reaction to a variety of agents including drugs, insect or spider bites, infections (bacterial, mycobacterial, viral, fungal), food ingestion (such as blue cheese), malignancies or some underlying diseases.

In most cases no cause will be found for the EAC.

Some people with EAC may have no symptoms whilst others experience mild itching associated with the rash.

EAC usually begins as a small raised pink-red spot that slowly enlarges forming a ring shape while the central area flattens and clears. There may be an inner rim of scale.

Sometimes the lesions do not form complete rings but grow into irregular shapes. As lesions resolve, there is no residual scarring but the skin may temporarily become redder.

One or several lesions of EAC may be localised to one area of the body or generalised over many areas. Lesions most often appear on the thighs and legs. They may occur anywhere on the body but typically spare the palms and soles.

The diagnosis of EAC is made by clinical examination. Further investigations may be needed to exclude other causes of annular rashes and to look for an underlying cause. In some cases a skin scraping is needed to exclude fungal infections that may mimic EAC. A biopsy of the skin may be needed in some cases.

EAC is usually self-limited which means that it usually resolves without treatment. However, eruptions may last from a few weeks to many years.

EAC has been known to resolve once the underlying diseases has been treated.

• Topical or systemic steroids may suppress the lesions but they do not prevent the recurrence of the eruption.
• Topical antipruritics and sedating antihistamines are used to relieve itching.
• The following medications have been reported as being beneficial: topical tacrolimus, topical calcipotriene (calcipotriol), oral metronidazole, subcutaneous etanercept and subcutaneous interferon-α.

The prognosis for EAC is excellent except in rare cases when it is associated with an underlying cancer or disease.