Matchbox Sign and the Dreaded Diagnosis

Image: Shutterstock/Thananya Apiromyanon

Every new patient is a mystery. You never know what is behind that exam room door that you are about to enter. You have already glanced at the chart before you go in. You know the patient’s age, gender, past medical history, past surgical history, allergies, etc. If you are lucky, you may have even seen a discharge or admission summary attached to the chart from a recent hospital admission. But you don’t know why the patient is really here today until you go in there. The appointment can turn into the most interesting case you have seen in your career and make your day or even make your head explode. I actually enjoy the suspense. It can be very interesting to unfold the mystery after going into the exam room. Time with your patient is limited, so it is also a race to get all of the information you need to diagnose.

Today, as I was told by the office staff, “Room 2 is ready for you,” I also got a “Good luck!” and a snarky smile, too. This was not a good sign… So, I looked at the chart and nothing, in particular, jumps out at me. Oh well… I took a deep breath, one last sip of my coffee, and knocked on the exam room door with curiosity. As I introduce myself, I looked at this neatly dressed, anxious, middle-aged woman. Nothing was alarming in her appearance at all. I asked, “What brings you here?” So, she starts to explain, “I have worms, doctor…They are everywhere! My primary care doctor wanted me to see you.”

She certainly grabbed my attention.

She continues, “I have worms coming out of my skin. They come out of my arms, legs, belly, face, butt, everywhere doctor! I can’t even sleep at night.” She showed me her arms, “Do you see them? They are right there, look closer!” She was serious. She truly believed that she has worms coming out of her skin. She was desperate for me to see them, too. It was heartbreaking. I almost wanted to see the worms, so I wouldn’t have to tell her that it’s in her head. She became hysterical when she looked at my face and sensed my hesitation. She knows that like many other doctors she had seen prior to coming to me, I didn’t see any worms.

“I am not lying, doctor!” she said and pulled out her phone. She started showing me close up pictures of various parts of her skin. “You see, the worms are here in the pictures, too!”

There were no worms in the pictures.

“How can you not see?” She was angry. She started to dig into her purse and took out a small plastic cup. “Here!” She screamed, “I brought some of the worms with me. These came out of my nose!” She handed me the cup. I look at it intently. There were very thin, almost translucent, white fibers in it. This is remarkable. I had seen a handful of such patients in two decades and heard about the “matchbox sign,” but I never actually saw it. Matchbox sign is when delusional parasitosis patients bring in small fibers or items that they believe are worms or parasites coming out of their body and put them in small containers like matchboxes to show during the doctor visit. I looked at the chart again. She had extensive labs done recently, all normal. She was not using illicit drugs. She had no history of exotic travel to suspect any skin parasites.

I took a deep breath, looked at the patient in the eyes, and tried to explain that while I have no doubt that she certainly believes that she has worms coming out of her skin, she does not actually have worms. What she had was a psychiatric condition with a delusion. She was devastated. I was willing to examine the fibers under the microscope to be completely sure. She got even more upset, got up angrily, and stormed out, cursing the staff on her way.

Every specialty or practitioner has a different diagnosis that they dread to see. Some even dread a patient that was added the day of their schedules that makes them cringe. For me, it is delusional parasitosis. As the patients are delusional, there is no convincing them otherwise. Occasionally I am able to calm them down just enough to offer them symptomatic treatment and basic labs if they have not been done by the numerous doctors they have already seen before coming to me. They rarely agree to get treatment. Unfortunately, these visits are almost always the source of mutual disappointment.

I look at my watch and, as usual, I am running behind. I start to open the next patient’s chart and wonder what is waiting for me behind that exam room door.

Gul Madison, MD, is an infectious diseases specialist in Philadelphia. She is a 2018–19 Doximity Author.

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