Lyme disease begins in up to 60 to 80% of patients as a slowly expanding reddish rash known as “erythema migrans”, typically 3 to 32 days after the bite of an infectious tick. This rash, which may not be apparent on dark-skinned people, usually begins at the location where the tick attached and expands slowly to several inches in diameter before disappearing within 3 to 4 weeks. Antibiotic treatment reduces the duration of the rash to about a week. Many patients experience fatigue, headache, fever, chills, and other flulike symptoms during the initial stage of illness.
Without treatment, other signs or symptoms may occur days to months later. These can involve the skin (multiple secondary rashes), musculoskeletal system (migratory pain in joints, tendons, muscles, or bones), neurologic system (severe headache, facial palsy, memory loss), and enlarged lymph nodes. More rarely, inflammation of the heart or eyes, or liver damage, may ensue, too.
People with untreated late-stage Lyme disease may begin to experience signs or symptoms months or years after infection, which may result in arthritic, neurologic, or further skin manifestations. Deaths attributable to Lyme disease are rare events: sudden cardiac deaths linked to Lyme carditis (inflammation of the heart) were reported during a 9-month period in 2013 for three young adults who resided in the northeastern United States.
Lyme Disease in Pets
Dogs are susceptible to Lyme disease and may develop arthritis or lameness, lethargy, loss of appetite, enlarged lymph nodes, or other clinical conditions. Consult a veterinarian if you suspect your dog has Lyme disease. Cats, horses, and livestock also may become infected but rarely develop clinical signs.