Multiple chemical sensitivity (MCS), discussed in your article, is a common symptom of several illnesses that I research (Allergic to the world: can medicine help people with severe intolerance to chemicals?, 20 September).
The article suggests that MCS should be treated, at least in part, as a mental illness. For decades, patients with complex illnesses have been told that it’s in their heads, and this is especially true for illnesses that predominantly affect females. Multiple sclerosis patients weren’t widely believed until MRI machines were invented. Until long Covid, ME/CFS patients often weren’t taken seriously, despite 25% of them being housebound from severe illness. Fibromyalgia patients were commonly dismissed until researchers discovered half of them have small fibre neuropathy.
Some 12.6% of Americans report hypersensitivities to common chemicals. Is it that unlikely that some people are more sensitive to certain exposures than others? It can take decades to identify biomarkers in complex illnesses, but that does not mean they aren’t real. People with MCS aren’t making it up.
Beth Pollack
Massachusetts Institute of Technology