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Victoria,
B.C.--Perfume
was a hot topic at the 7th Congress of the European Society of Contact
Dermatitis this year in Copenhagen, where toxicologists made up
approximately half of the 400 delegates. Daniel J. Hogan, MD, professor
of medicine and pediatrics, chief of dermatology, Louisiana Statue
University Health Sciences Centre, Shreveport, was in attendance
and presented highlights at the annual meeting of the Canadian Dermatology
Association.
Perfume
More than 4,000 molecules can be found in a perfume; 26 are well-known
allergens. The axillae are commonly by allergy to fragrances in
deodorants, and occupational risk for fragrance allergy exists for
massage therapists and nursing home workers.
Swedish studies have shown that it is the oxidation of the terpenes
in perfumes that create the allergen, and hydroperoxides are the
most potent sensitizers. "Of course we patch test people to
the unoxidized pure chemical, which might give a negative result.
We actually have to test them to the oxidized form, but when that
will become commercially and readily available is unknown,"
Dr. Hogan remarked.
Chloroatranol, an allergen found in oak moss absolute, is especially
potent in fragrance. Dose-response tests have shown there is no
safe level, and the Europeans are discussing banning it. Cheap fragrances
found in household products, primarily Lyral and Citral, are also
of concern. So in Europe next year, legislation will attempt to
force perfume manufacturers to list known allergens on their labels,
Dr. Hogan reported. There was a further suggestion at the meeting
that there should be a best-before date on perfume labels.
Preservatives
Methyldibromoglutaronitrile (MDGN, Euxyl K(tm)) causes severe allergic
contact dermatitis, and patch-test reactions are strong and severe.
"We tend to think that leave-on products cause more problems
than products you wash off, but Euxyl K is causing a lot of problems
in liquid soap that you wash off," Dr. Hogan said. Furthermore,
the product accumulates. Repeat Open Application Tests show that
100 ppm, four times daily, is equivalent to putting on 400 ppm,
once daily.
Formaldehyde donors (eg, Germal 115) were widely discussed, as they
seem to cause more allergic contact dermatitis than formaldehyde
itself, he said.
Metals
The Euro coin consists of two metal layers, setting up a small electrical
current. When in contact with sweat, studies have shown that more
nickel is released than if the coin were made of pure nickel, Dr.
Hogan reported.
Food
Due to the scare from Mad Cow disease, hydrolyzed wheat protein
has been substituted for bovine collagen in topical products. However,
some people are becoming sensitized to the hydrolyzed wheat protein
through the skin, and some have reactions to it when it is present
in food.
Machinists
Monethanolamine is the most important allergen in cutting fluids
and should be included in patch tests for machinists. In addition
fragrances may be being added to the cutting fluids. Odour masks
may account for a 2.6-fold increase in fragrance allergy in German
machinists. The well-known allergen, colophony, may be found in
soldering fluxes, soap oil and varnishes.
Plants
Allergies to the primrose plant (Primula obconica), common in England,
are declining due to new species of the plant being cultivated.
A Portuguese paper reported that allergic contact dermatitis to
altsromeria cannot be avoided through wearing various gloves. Nitrolatex
and polystyrene gloves offer some protection kitchen workers.
Topical retinoids
One paper reported that the Chinese appear to be the most susceptible
to irritant contact dermatitis from topical retinoids, followed
by Indians and Malaysians, which may be of interest to Canadian
dermatologists who practice in culturally diverse areas, Dr. Hogan
reported.
Immunology
A number of papers reported that interleukin-8 is quite specific
for allergic contact dermatitis. There were also reports that memory
T cells persist at the test site long after the patch test reaction
has faded.
Literature
review
Denis Sasseville, MD, chief of dermatology, McGill University Health
Centre, Montreal, presented some interesting cases in contact dermatitis
at the annual meeting of the Canadian Dermatology Association.
The North American Contact Dermatitis Group has published its latest
research on the most common allergens (Marks JG, et al, Am
J Contact Derm 2003;14:59-62). Nickel is still the most common
allergen and its rate keeps increasing, being now at 16.2%. Thimerosal,
gold thiosulfate and bacitracin are among the 10 most common allergens
and are not routinely tested in TRUE Test or the European Standard
series. Of particular interest is that the rate of chromate allergy
has more than doubled since the group last reported in 2001, he
said.
Diclofenac
Reactions to topical diclofenac have shown up in three papers.
One was the case of a 55-year-old man treated with Solaraze(r) gel
for his actinic keratosis who developed severe allergic contact
dermatitis (Ker, OA, Kavanagh, G, Horn, H Contact Derm 2002;47:175).
His patch test was positive for the gel and its incredients. He
developed 3+ reactions to Solaraze and to diclofenac.
Another was a case of a 40-year-old man who developed photo allergic
dermatitis to diclofenac following treatment with Voltaren Emulgel(r)
and subsequent sun exposure (Montoro J, Contact Derm 2003;
48: 115). His patch test was negative to the gel and its ingredients.
The photo patch test was positive for both the gel and diclofenac
1% in petrolatum.
Another was a woman with a history of shortness of breath with oral
diclofenac, and experienced one anaphylactic episode following use
of a diclofenac suppository. Following her patch test with diclofenac
in petrolatum, she experienced anaphylaxis within 15 minutes. (Jonker
MJ, Bruynzed, Contact Derm 2003;49:114-115).
A new topical formulation of diclofenac (Pennsaid(r)) has recently
been introduced to combat musculoskeletal pain. It is mixed with
DMSO to increase penetration, and may or may not increase saturation
of Langerhans' cells. Dr. Sasseville said he expects to see patients
in future who react to this formulation.
Hair products
A permanent wave product introduced for the first time in a hair
salon caused a hair stylist to react severely within two weeks of
being exposed to cysteamine hydrochloride (Landers, MC, Law, S,
Storrs, FJ, Am J Contact Derm 2003;14:157-160). The product
has been on the market 11 years and is considered minimally damaging
to hair, it requires no mixing, and is easy to administer.
Prep Swabs
A 60-year-old woman complained of dermatitis each time she had venipuncture,
where the site was swabbed with alcohol. She patch-tested positive
to various brands of swabs, but was negative to isopropyl alcohol.
UV-reflectometry showed two absorption peaks in the alcohol used
in this case that were not present in chemical-grade alcohol, but
the allergen remains unknown (Taylor JS, Erkek E, Leow YH, Jacobsen
DW, oral communication at the 15th Annual Meeting of the American
Contact Dermatitis Society, Washington, DC, February 5, 2004).
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