Porphyria is a well-defined group of disorders caused by abnormalities in the chemical steps that lead to heme production. Heme, a molecule needed by all of the body’s organs, is found mostly in the blood, bone marrow, and liver. Heme is a component of hemoglobin, the molecule that carries oxygen in the blood .
The signs and symptoms of porphyria vary among the types. Some types (called cutaneous porphyrias) cause the skin to become overly sensitive to sunlight. Exposed skin may develop redness, blistering, infections, scarring, changes in pigmentation, and increased hair growth. Other types of porphyria (acute porphyrias) mostly affect the nervous system. Appearing quickly and lasting from days to weeks, acute signs and symptoms include abdominal pain, vomiting, constipation, and diarrhea. During an attack, a person may also experience muscle weakness, seizures, fever, loss of sensation, and mental changes such as anxiety and hallucinations. Two forms of porphyria have a combination of acute symptoms and symptoms that affect the skin . Most forms of porphyria are inherited.
In contrast, “multiple chemical sensitivity” (“MCS”) is a medically disputed term used to describe people with multiple troubling symptoms they attribute to environmental factors. Many such people are seeking special accommodations, applying for disability benefits, and filing lawsuits claiming that exposure to common foods and chemicals has made them ill. Their efforts are supported by a small network of physicians who use questionable diagnostic and treatment methods. Practitioners who promote MCS as a diagnosis claim that it is caused by extremely low levels of chemical substances found in the environment. However, no scientific tests have ever been able to detect an organic basis for the diagnosis, and no major medical organization recognizes MCS as a clinical disease. Instead of testing their claims with well-designed research, its advocates promote them through publications, talk shows, support groups, lawsuits, and political maneuvering .
In the 1990s, partly in response to the fact that courts were not recognizing MCS as a disease, many proponent doctors began inappropriately diagnosing “disorders of porphyrin metabolism” in large percentages of their patients . Although the porphyrias are rare, these doctors claim that many MCS patients have porphyrin abnormalities and that the same environmental substances can trigger both conditions . Their strategy was laid bare in a 1996 article in Our Toxic Times which said that diagnosing one of the porphyrias was advantageous because “they have a recognized diagnostic code” and “doctors who don’t know about MCS or don’t believe in it do believe in porphyria.”  Another issue of the newsletter contained a “porphyria symptom check list” of about 90 “possible symptoms.”  Porphyrias do not have that many symptoms.
Expert reviewers have concluded that the proposed relationships between MCS and porphyrin disorders should be considered “speculative and unestablished” and do not justify using any measures that are appropriate for treating porphyrias . In 1995, the Washington State Department of Labor and Industries and the Washington State Medical Association issued an authoritative guide to diagnosing porphyrin disorders .
Flawed Laboratory Testing
Most of the purported association of porphyria with MCS is based on results obtained with the urinary coproporphyrin assay, a laboratory test performed by the Mayo Clinic. However, the test has never been validated. Although “MCS” patients reportedly showed modest increases in urinary coproporphyrin excretion, this is a common finding found in many people without symptoms and also in patients with diverse other conditions such as diabetes mellitus, heavy alcohol use, liver disease, and many kinds of anemia. In 1997, two porphyria experts at the University of Massachusetts Medical Center noted these facts and warned that the test was not reliable, had not been validated, and should not be used . In 1999, two Mayo researchers concluded that 56 out of 64 of the enzyme tests performed by the Mayo laboratory should not have been ordered and that there was “substantial overordering” of other tests and “inadequate physician knowledge about the interpretation of test results in the evaluation of acute porphyria.”  Their report did not reveal the fact that most of the inappropriate enzyme tests were ordered by William Morton, M.D. of Oregon Health Sciences University, who was the MCS-porphyria connection’s leading advocate.
Court and Regulatory Actions
I know of three cases in which judges gave no credibility to a porphyrin-MCS connection.
In 1991, a trial court ruled that plaintiff’s immune assays, including calla and porphyrin antibody testing, performed by Dr. Bertram Carnow, were inadmissible because plaintiff failed to prove that the testing was “acceptable to at least a substantial minority of the relevant scientific community.” 
In 2001, an administrative law judge ruled against a claimant who sought compensation for alleged work-related porphyrin deficiency and relied on testimony of Dr. Morton. According to a case summary I found on the Internet:
The [Administrative Law Judge] rejected Dr. Morton’s opinion because it was clear that Dr. Morton’s opinion was not based upon the same level of intellectual rigor that characterizes the practice of experts in this field of medicine. Dr. Morton was outside of the medical mainstream and his analysis was non-scientific since his description of the disease and environmental causes was so broad as to be meaningless. He also had no scientific basis for rejecting known and accepted testing techniques which were objective, reproducible, and reliable in terms of locating levels of enzyme residue that would be created by this particular disease .
In 2004, the Oregon courts ruled against a woman in a similar case, which the appeals court summarized this way:
Throughout 1996 and 1997, after leaving her employment with Lane County, petitioner continued to see her physicians for complaints of chemical reactivity. In May 1997, Dr. Morton, a specialist in occupational medicine, diagnosed petitioner as having “active porphyrin metabolic dysfunction” (i.e., porphyria). He explained that people “with porphyria traits are abnormally susceptible to porphyrogenic substances,” such as the fumes from certain types of chemicals and substances. He further explained that, “Once activated, porphyria symptoms do not always stop when the initiating exposure stops.” In connection with a workers’ compensation claim that petitioner filed with Lane County, petitioner was also examined by Dr. Burton, a specialist in medical toxicology and occupational medicine. In Burton’s opinion, petitioner’s history and symptoms were not consistent with a diagnosis of porphyria, and petitioner does not suffer from that condition. Burton also opined that the diagnosis of MCS given by one of petitioner’s treating physicians was not a legitimate medical diagnosis. In Burton’s view, physicians use a diagnosis of MCS to explain a variety of nonspecific symptoms otherwise not organically explainable 
In 2001, the Oregon Board charged Morton with inappropriately diagnosing “porphyria” with the result that patients received inappropriate treatment from him or other providers . In 2002, rather than facing the charges, Morton agreed to retire his license . Because Morton was by far the leading proponent of the MCS-porphyria connection, his “retirement” and judicial thrashings signaled the end to what Dr. Burton recently dubbed “the porphyria epidemic.” 
- Porphyria. Genetics Home Reference Web site, Nov 2006.
- Barrett S. A Close Look at “Multiple Chemical Sensitivity”. Allentown, Pa: Quackwatch Inc., 1998.
- Wilson C. Porphyrinopathies in the MCS community. Our Toxic Times 7(3):1–4, 1996.
- Morton W. Chronic porphyrias’ role in MCS. Our Toxic Times 6(8):22–24, 1995.
- Wilson C. Hallmark feature of MCS and porphyria. Our Toxic Times 7(10):1–8, 1996.
- Porphyria symptom check list. Our Toxic Times 7(6):20–21, 1996.
- Collaborative guidelines on the diagnosis of porphyria and related conditions. Olympia, Wa.: Washington State Department of Labor and Industries, Oct. 18, 1995.
- Daniell WE and others. Environmental chemical exposures and disturbances of heme synthesis. Environmental Health Perspectives 105(Supplement 1):37–53, 1997.
- Hahn M, Bonkovsky HL. Multiple chemical sensitivity syndrome and porphyria. A note of caution and concern. Archives of Internal Medicine 157:281-285, 1997.
- Mattern SET, Teffari A. Acute porphyria: The cost of suspicion. American Journal of Medicine 107:621-623, 1999.
- Newman v. Stringfellow. Case No. 165994, California Superior Court, Riverside County, Jan 17, 1991.
- Dr. Morton (of OHSU) opinion on porphyria rejected. NWLAA Case Law Review, July-August 2001.
- Judicial review. Henderson v. Public Employees Retirement Board. Oregon Court of Appeals 99-0421;A1187341, filed Dec 8, 2004.
- Complaint and notice of proposed disciplinary action. In the matter of William Edwards Morton, MD Before the Board of Medical Examiners, State of Oregon, Dec 3, 2001.
- Stipulated order. In the matter of William Edwards Morton, MD before the Board of Medical Examiners, State of Oregon, Jan 17, 2002.
- Burton B. E-mail message to Dr. Stephen Barrett, Jan 21, 2010.
This article was revised on January 22, 2010.