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What is erythema migrans?

Erythema migrans is an expanding skin rash associated with early Lyme disease. It may be circular or oval and does not always have the classic bullseye appearance.

Reviewed by VuxLore® Knowledge Team For Everyone

Short answer

Erythema migrans is an expanding skin rash associated with early Lyme disease. It may be circular or oval and does not always have the classic bullseye appearance.

At a glance

The rash usually expands over time and may appear days to weeks after infection. Appearance varies and qualified medical assessment is important.

Key takeaways

• Not every rash has central clearing.

• Not every Lyme case produces a noticed rash.

• Seek prompt medical advice for a spreading rash after possible exposure.

More varied than the familiar symbol

Public images often emphasise a red ring with a pale centre, but erythema migrans can be evenly coloured, oval or otherwise different from that textbook pattern.

Clinical context matters

A clinician considers the rash, exposure history, location and other symptoms. Do not wait for a perfect bullseye before requesting advice.

Sources and further reading

UK Lyme disease guidance and data

For current UK clinical advice, public-health guidance and surveillance data, consult these primary national sources.

  1. Lyme disease — NHS opens in a new tab
  2. Lyme disease: diagnosis and management (NG95) — NICE opens in a new tab
  3. Lyme disease: management and prevention — UKHSA opens in a new tab
  4. Lyme disease surveillance dashboard — UKHSA opens in a new tab
  5. Lyme disease — NHS Inform Scotland opens in a new tab