The recent switch from methotrexate to azathioprine has caused breathing difficulties. Though it’s nothing life threatening, my doctors are not sure why.

For most mammals, breathing is easy. Astronaut Chris Hadfield, on Darren Aronofsky’s “One Strange Rock,” calls it the most natural thing humans do. Aronofsky (of Black Swan fame) then shows a baby inhaling minutes after being born.

Like most healthy people, for most of my life, I took breathing for granted. I swam as a child. I ran cross-country in high school. I hiked four of Colorado’s Fourteeners. I played schoolyard football.

I also took my lungs for granted. I built campfires. I smoked the occasional cigar. Nothing ever bothered them, even after one had to be deflated (then later inflated) so my orthopedic surgeon could access and fuse my spine.

Dermatomyositis and Lung Involvement

Dermatomyositis has changed all that. Without prednisone or hydroxychloroquine, I feel short of breath. My chest feels tight. Breaths become heavy, even if my lungs otherwise function.

Shortness of breath can be a symptom of dermatomyositis because the immune system attacks the chest muscles, restricting breathing. This is most likely the cause of my issues.

Breathing difficulties could also be the result of aspiration pneumonia: Muscle inflammation causes difficulty swallowing, sending liquids and food down the wrong pipe, eventually causing an infection.

Long-Term Possibilities: Interstitial Lung Disease

Most concerning, dermatomyositis can lead to interstitial lung disease. In short, the immune system malfunctions as it tries to repair damage to the lungs. It scars and thickens the tissue around the air sacs, making it difficult to breathe and to get enough oxygen into the bloodstream.

Fortunately, my pulmonary function test in September came back normal. So too did my chest x-rays and high-resolution CT scans. Three weeks ago, I also had an EKG indicating my heart is very healthy.

Short-Term Possibilities: Medications

Ironically, the very drugs designed to keep my immune system at bay and help me breath can also cause lung damage. Methotrexate has been known to cause interstitial lung disease. So too have many anti-inflammatory drugs used to control autoimmune diseases, such as rituximab (Rituxan).

Azathioprine, the medication I am currently taking, can cause chest pain and increase your heart rate. Of course, those are also symptoms of dermatomyositis.

I returned to my rheumatologist earlier this week because I thought the drugs were causing the issues. He disagrees and believes my symptoms could be stress and anxiety.

Reversing the Cause and Effects of Breathing Difficulties

Two days later, after experimenting with taking the drugs at different times of day, I’m convinced we’re both wrong. I reversed the cause and effect, leading him to look at my symptoms as drug related rather than effects of the dermatomyositis itself.

I reversed the cause and effect of my breathing difficulties.

Azathioprine seems to clear up my rashes and keep my immune system from attacking my chest and shoulder muscles. But as soon as it wears off, the chest tightness and shortness of breath return. I get headaches. My heart speeds up. I become fatigued and want to head to bed.

In time, I think my doctors and I will fix this. Increasing the dose staved off the breathing difficulties all day, then they start to get better again a few hours after the drugs leave my body. Plus, switching medications is very hard on any body being attacked by its immune system.