Red, tingly foot rash stumps patient and doctor

She was 80 years old, and her blood pressure was out of control. She didn't care about that, though. She was more concerned about her feet. They had been red for a couple of months, and now they were getting "tingly." They didn't hurt, and they weren't swollen. On exam, there was some redness of the tops of her feet that cut off abruptly just before her toes. There was some similar reddish discoloration of her knees as well. Her feet weren't swollen, and they had good circulation.

I was much more concerned about her irregular heartbeat, so by the time I finished with an EKG (which was fine) and addressing her blood pressure (which wasn't), I'd almost forgotten about her feet.

"Probably contact dermatitis," I told her. "Try some over-the-counter hydrocortisone cream for it."

Six weeks later she came back. Her blood pressure was much better, but her feet weren't. They were still red and tingly and had begun to itch. When I examined her skin again, there were patches of slightly swollen, warm redness that now spread over her shins and the tops of her feet, again cutting off right before her toes, almost in a sandal pattern. I checked the rest of her skin carefully, but didn't see anything else.

At this point, I had no idea what it was, so I suggested she see a dermatologist.

"Oh no," she said. "I don't want to see another doctor right now."

"Well, then," I suggested, "why don't you try some cool compresses?"

Five months later, the rash was still there, becoming more itchy and more annoying. Finally, she accepted a dermatology referral.

It took two additional months for her to get there, whereupon the dermatologist did a biopsy and sent her for blood work, which produced the answer.

The dermatologist ordered a test for Lyme disease, despite the fact that the patient had no history of a tick bite or any other Lyme symptoms.

The test was strongly positive.

The patient had acrodermatitis chronica atrophicans, a late manifestation of infection with the germBorrelia burgdorferi, also known as Lyme disease.

Lyme disease is transmitted by the bite of an infected nymph deer tick. In order to pass the germ to a human, the tick has to be attached for more than 24 hours, but it's so small that the bite often goes unnoticed. Peak season for Lyme disease mirrors that for the deer ticks: late spring, summer, and early fall.

The germ that causes Lyme disease is the same type of organism that causes syphilis. They're called spirochetes, and although they are easy to kill with simple antibiotics if you treat them early, they are notorious for going into hiding in different body tissues, only to come out months, years, or, in the case of syphilis, even decades later. They can produce devastating symptoms, which is why early treatment is so important.

Although some people have no symptoms at all when first infected with Lyme, many will become ill with either an expanding red rash at the site of the tick bite (the so-called bull's-eye) or a flulike illness consisting of fever, chills, body aches, and malaise. Whenever I see "flu" in the summer, I think of Lyme disease. These are the early manifestations, so-called primary Lyme disease.

Both the rash and the flulike illness will resolve, even if left untreated, but the germ can spread elsewhere in the body and, weeks to months later, cause symptoms of secondary Lyme disease. The most common of these is Bell's palsy, a temporary paralysis of one side of the face that's more alarming than dangerous. Secondary Lyme disease can also affect conduction of electricity through the heart, occasionally requiring a pacemaker.

Late, or tertiary, Lyme disease manifestations occur months to years after initial infection, and include arthritis (typically of large joints such as the knees and shoulders) and inflammation of the brain and nerves. Symptoms can include weakness, severe nerve pain (neuropathy) in any part of the body, and trouble thinking, which can also include a wide variety of psychiatric manifestations.

There is no such thing as "chronic Lyme disease," despite a manufactured controversy to the contrary. Treatment at any stage of the disease consists of a somewhat longer course of antibiotics (two to four weeks) than would be prescribed for simple bacterial infections (7 to 10 days.)

This kills the germ, although some symptoms may persist.

My patient was lucky. She took the antibiotic doxycycline for three weeks, and although she needed medication for nerve pain for a few more months, eventually, her symptoms resolved completely.

in Phoenixville. She blogs at http://dinosaurmusings.wordpress.com.