Diagnose Lyme disease from rash, doctors told

Doctors should not wait for blood test results to diagnose patients with Lyme disease if they have a “bull’s eye” rash, health officials have said.

Early laboratory tests may not detect the infection and potentially slow diagnosis and the start of treatment, new draft guidance published by the National Institute for Health and Care Excellence (Nice) states.

However, erythema migrans, a red skin rash linked to the disease which can resemble a bull’s eye, is present in around two-thirds of cases.

“For most people with Lyme disease, a course of antibiotics will be effective, so it is important we diagnose and treat people as soon as possible,” Professor Gillian Leng, director of health and social care at Nice, said.

“A person with Lyme disease may present with a wide range of symptoms, so we have clear advice for professionals about the use of lab tests for diagnosis and the most appropriate antibiotic treatments.

“If a characteristic bull’s eye rash is present, healthcare professionals should feel confident in diagnosing Lyme disease.”

Lyme disease is an infection transmitted by infected ticks and a circular rash usually appears between one and four weeks after someone is bitten.

Tests can check for antibodies in the blood.

However, these may not appear until up to eight weeks after the patient is bitten.