Author: Dr Ian Coulson, Consultant Dermatologist and Editor-in-Chief, 2022.
Edited by the DermNet content department
This 8-year-old boy has returned from a hiking holiday with his parents in rural England. He has developed a slowly spreading red ring over his chest. He does not recall any bites. He is otherwise well.
The subtle but slowly spreading red ring is characteristic of erythema migrans, the early cutaneous manifestation of Lyme disease.
Inoculation occurs after a bite from an infected tick. The rash often starts days after inoculation of the skin with a causative bacterium, Borrelia burgdorferi, and slowly spreads over a number of weeks.
It is usually the case that the tick needs to feed from the human victim for at least 24-hours in order for infection to occur. A significant proportion of those infected have no recollection of the tick attachment.
Early associated symptoms include fever, chills, muscle and joint aches, swollen lymph nodes, and erythema migrans (in about 80%). Late symptoms include arthritis, carditis and arrhythmias, neuritis, and encephalitis.
Late skin manifestations include acrodermatitis chronica atrophicans and lymphocytoma cutis.
Children under the age of nine should be treated with amoxicillin or azithromycin if they have non-focal symptoms. The presence of carditis or central nervous system disease would require intravenous treatment.
