Along with the many pleasures of being outdoors in the summer, unfortunately we must also contend with a few downsides, like bugs that bite. In Act 1 of my medical career I was a specialist in infectious diseases. Tick-borne illnesses are at the intersection of infectious diseases and dermatology. As in most of the country, tick-borne illnesses are on the rise. According to the CDC, the number of people affected by tick-borne illnesses has tripled since 1990. Even if we are not walking barefoot in a field, a tick occasionally sneaks a ride into the house on Leo!
The most important tick-borne illnesses in our area are Lyme disease, Rocky Mountain Spotted Fever (RMSF) and Ehrlichiosis. Lyme disease is transmitted by the black legged tick (deer tick, Ixodes scapularis). ~95% of reported cases occur in 14 states, including Virginia. The tick nymphs that transmit most Lyme disease are tiny and the biting tick may not be noticed. Peak season is spring and summer, especially May-June. The tick must be attached for ~30 hours to transmit Lyme disease. The characteristic rash is the “bullseye”- a red ring with central clearing that may move around. This rash occurs early after a tick bite (days to weeks but usually by 7 days) and affects about 75% of people who get infected in the localized stage of Lyme disease. The blood tests for Lyme may be negative during this early phase. Not everyone with Lyme disease develops this type of rash and the rash can take a variety of forms, so absence of the classic rash does not rule out Lyme disease. There are pictures of the ticks and the rash on the CDC website .
The best way to prevent Lyme disease is to take precautions including wearing long-sleeves and pants, tucked in, when outdoors in summer and especially in the woods or shady areas. Clothing and exposed skin may be treated with repellants like permethrin or DEET. You should also make a habit of showering and doing a tick check after spending time outdoors. If you find a tick attached, remove it by the head with fine-tip tweezers. In areas with high rates of infected ticks, including Virginia, a single dose of doxycycline given within 72hr of the tick bite may reduce the risk of Lyme disease. If you find a tick attached, you should call your doctor to discuss whether prophylaxis is right for you.