The strange rash was puzzled by the doctor. Was it an insect bite?

Timing issues

I had the man repeat his story. There were no new clues. I thought about the possibility. Lyme disease causes an eye rash with the famous central clearance, but the time courses were all wrong. The deer tick vector must be worn on the body for at least 36 hours in order to pass the gift of Lyme Spirocheta. And it takes a few days for the rash to appear. Was this caused by a toxin injected by a bite or sting? The time course seemed like that. Insect bites usually respond immediately. Brown recluse spiders can cause a delayed response, but in severe cases they can cause blisters and necrosis of the skin. And how does it appear on the other leg? Does that mean it had invaded his bloodstream and spread through his body? Should patients begin with doxycycline, an antibiotic used to treat most infections caused by tick bites? However, the patient did not feel unwell. He was worried about the rash. And so did I.

Dermatologist Keith Chort teaches a resident with me in our clinic. This was his day of education. Raman and I found dermatologists chased by a handful of residents. He was not with the patient, so we briefly described our patient. I brought Choate to the hospital room. Residents were watching from the door. Choto introduced himself to the man, immediately saw the twin rash and asked only one question.

One simple question

“Are you using triple antibiotic ointment?” he asked the patient. Triple Antibiotic Ointment is a mixture of three topical antibiotics: Neomycin, Polymyxin B and Bacitracin. Although it is marketed under the brand name Neosporin, a generic version of the mixture is available, marketed under the name Triple Antibiotic Ointment. The patient was using this ointment, he told Choate. But only a few times, as it seemed useless. “Well, never use it again,” Chot advised. The rash was not an infection, but a help from topical antibiotics, but an allergy caused by it. This ointment is one of the most common causes known as allergic contact dermatitis (ACD).

The skin is rich in white blood cells, which protects the body from intruders who try to enter through it. This is the largest organ in the body. In allergic contact dermatitis, benign substances in contact with the skin are mistaken for predators and cause a protective inflammatory response. Several substances, including neomycin and bacitracin, two of the three antibiotics in this ointment, have been found to be frequent causes of this type of false protective reaction. In one large study of surgical patients, allergic contact dermatitis developed in over 4% of patients exposed to the ingredients in the three antibiotic ointments. Along with common ingredients in lotions and fragrances, it is one of the top 10 causes of ACD.

Chort recommended a powerful steroid cream to quench the inflammation and speed the resolution of the rash. But the dermatologist warned that it would take some time to warn.

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Upon leaving the room, Raman asked Chote how the rash spreads to the other leg. His answer was simple, holding clues to how he understood it. He reminded her that it was contact dermatitis. When the man crossed his ankle or put his feet side by side, perhaps while he was sleeping, the ointment on one foot was in contact with the other.

He talked to the patient a week after he started the steroid cream. The rash gradually disappeared. He went out there in the garden, feeling a bite, looking for bushes and grass around him, looking for clues as to what was his clue. He probably hasn’t found the culprit. There are no ant hills or beehives. There are no spear-shaped plants or grass. There are no spiderwebs. He told me it was a mystery. However, on average, he will now wear long pants, socks and shoes to mow the lawn.