Hairdressers at Risk for Occupational Asthma
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The bleaching agents used by hairdressers can cause occupational asthma and rhinitis, say researchers here.
The finding comes from an eight-year series study of 47 hairdressers who were referred to the allergy and immunology unit at the Scientific Institute of Pavia here, according to Gianna Moscato, M.D., head of the allergy unit.
The hairdressers—mostly young women—had been exposed to persulfate salts and other potential allergens for an average of seven years before they were referred because of asthma symptoms, Dr. Moscato and colleagues reported in the November issue of the journal Chest.
While several other studies have examined the connection between occupational asthma and hairdressing, Dr. Moscato said, “to our knowledge, this is the largest group of hairdressers observed in a clinical unit to date.”
On the basis of a specific inhalation challenge, 24 of the patients were assessed as having occupational asthma, due in 21 cases to persulfate salts found in bleaching agents, to permanent hair dyes in two, and to latex in one.
The remainder of the patients were diagnosed as having transitory irritative asthma, Dr. Moscato said, possibly because of other factors found in salons, such as vapors, solvents, perfumes, and dust.
Thirteen of the 24 patients with occupational asthma also had occupational rhinitis, due to persulfate salts in 11 cases and to paraphenylenediamine, a constituent of hair and textile dyes, in two patients.
Also, 11 of the 24 patients also had dermatitis, the researchers found.
Comparing the patients with occupational asthma owing to persulfate salts with those who did not have an occupational condition, the study found:
- Those with occupational asthma were significantly more likely to have a positive response on a metacholine test (p=0.0001).
- They were more likely to have a negative result on a bronchodilator test (p=0.0082).
- They were more likely to be positive on a stop/resume test (p=0.0006).
- Their average maximum fall in forced expiratory volume in one second (FEV1) was 29% (with a range from 24% to 34%).
Only half the patients with occupational asthma had a family history of allergy, Dr. Moscato and colleagues found, confirming earlier studies that suggest that such a history is not a strong risk factor in the hairdressing industry.
Interestingly, she said, all the patients whose work history included direct contact with bleaching agents had a positive result on the stop/resume test, but so did 13 of the 23 patients who were not diagnosed with occupational asthma.
There are two implications, she said:
- The finding underlines that clinical history should be confirmed by objective tests.
- And—because negative stop/resume tests were only found in patients who were also negative on the inhalation challenge—the finding also suggests that the test can help predict the outcome of the inhalation test.
The researchers were also unable to find evidence of the involvement of an immunoglobulin E-mediated mechanism, Dr. Moscato said.
“At present, the mechanism of asthma due to persulfate salts still remains unknown and requires further studies,” she and colleagues wrote.
In the absence of such a mechanism, they concluded, the specific inhalation challenge remains the gold standard for diagnosing persulfate asthma.
Primary source: Chest
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