Long-Term Immunologic Sequelae Secondary to Tea Tree Oil Allergic Contact Dermatitis

A long time ago, somebody (I forget who, but I think it was a family that is very close to my own family; they were classmates of my parents in medical school) gave me a small sampler set of four or five men’s cologne. I enjoyed using them once in a while, and noticed that within this small collection there were definite differences. One seemed to be floral; another seemed to be based on spices; and another seemed to be more musky, more animal. The colognes were not labeled, but I did Google searches and was able to identify most of them online (I have since forgotten what each of them were!).

Then one day (probably 2001 or 2002) I noticed a patch of dry skin, and self-diagnosed myself with ringworm, which I had when I was a child, and which is very easily treated with antifungal ointments. Instead of using conventional medicine, for some reason I thought I’d try “alternative medicine” and treat it with topical tea tree oil. The patch of dry skin seemed to redden, and I thought that maybe the ringworm was getting worse. So I kept applying the tea tree oil. The reddened skin got even redder. I kept applying the tea tree oil. The very red skin started to blister and ooze. Finally, I figured out what was going on. The ringworm wasn’t getting worse. It was the tea tree oil itself that was causing the skin reaction. I immediately stopped applying the tea tree oil, and my skin cleared up completely. And the ringworm was gone.

But the tea tree oil was not through with me. I discovered that ever since then, I am allergic to my colognes; the tea tree oil had induced some sort cross-sensitivity to complex aromatic (the word evokes carbon rings, with alternating double bonds) organic compounds. And I found that I could no longer use the brand of antiperspirant that I had been using; now I use a hypoallergenic one. Years later, I looked up tea tree oil on PubMed (the national database of peer-reviewed biomedical research literature, and discovered a case report that described my case almost exactly. This case report included graphic photos that looked very much like the skin reaction I experienced. Interestingly, the patient in the case report was Chinese, and I am part Chinese; I wonder whether certain ethnic groups are especially sensitive to tea tree oil.

And years later, every once in a while, I’ll try my old brand of antiperspirant. I am still allergic to it. The immune system can remember for a long time; it has memory cells.

One more tangential link in this Thought Chain: memory cells makes me think of the song Memory, the most famous number from the musical Cats.