A cosmetic is legally defined as a product that enhances appearance, aids in personal
hygiene, and does not affect the structure or function of the skin. Therefore, cosmetic
products contain no active drug ingredient. Sometimes the division of cosmetics
and over-the-counter drugs is not always clear, for example the recent hair regrowth
treatment, topical minoxidil (Regaine / Headway), which has been shown to cause
allergic contact dermatitis of the scalp
Cosmetics can be broadly divided into the following groups:
- Decorative products e.g. make-up
- Nail care products e.g. varnishes and removers
- Skin care products e.g. moisturizers
- Soaps & bath additives
- Shaving products e.g. foams, aftershave lotions
- Oral Hygiene products e.g. toothpaste & mouthwashes
- Hair Products e.g. shampoo, dyes & regrowth treatments
- Sun Protection products
- Feminine Hygiene products
- Fragrances e.g. perfumes & colognes
Deodorants & Antiperspirants Technically because they reduce or decrease
sweating, which affect the function of the skin, they should be considered drugs
It can be seen, therefore, that cosmetics are an important part of our daily life.
It is estimated that the average adult uses at least 7 different skin care products
each day, so its not surprising that reactions to these products are very
common. Reactions can be seen after the first application or after years of use.
In New Zealand, like the rest of the developed world, there is a trend towards using
"natural products", with the misconception that natural products are "healthier"
and cause fewer reactions than artificial products. This myth is debunked when people
are reminded that most allergens are "natural proteins.
Unlike drugs, cosmetics do not undergo governmental approval before marketing. The
cosmetic industry is primarily self-regulated (by The Cosmetics, Toiletry, and Fragrance
Cosmetics, Toiletry, and Fragrance Association (CTFA)
CTFA represents the industrys interests at the local, state, national, and
international levels, promoting voluntary industry self-regulation and reasonable
governmental requirements that support the health and safety of consumers.
CTFA has approximately 600 member companies. Active members are manufacturers and
distributors of finished products. Associate members are suppliers of ingredients,
raw materials, packaging, and other services used in the production and marketing
of finished products, as well as consumer and trade publications.
CTFA also supports the Cosmetic Ingredient Review (CIR), a program it helped establish
in 1976 which assesses the safety of ingredients used in cosmetics in an unbiased,
independent forum with an expert panel comprised of world-renowned physicians and
Cosmetics Regulations in New Zealand
Cosmetics in New Zealand are only self-regulated by CTFA. The CTFA in NZ was formed
in 1972 by a core group of cosmetics companies who were manufacturing their products
in NZ at that time. In NZ there is a reasonable code of practice through the local
CTFA. The problem arises where cosmetics are brought in from Asian countries where
no similar requirements are applied. Some of these products can have undisclosed
allergens, including peanuts.
What is even more worrying is the fact that there are at present no regulations
in New Zealand that cover cosmetic ingredient labelling. In October 1991, the Cosmetic
Ingredient Labelling Regulations were introduced in Australia. These regulations
define the term cosmetic product and require that all ingredients be
listed in descending order of concentration (although no naming convention is specified
nor is there a minimum print size requirement apart from it being legible). This
is a major step in helping consumers become aware of exactly what they are rubbing
into their skin and putting in their hair. In New Zealand it is still possible to
buy cosmetics with no proper labelling, with known allergens omitted from the label
or with the term "hypoallergenic" used loosely on the label.
In USA a cosmetic can be removed from the market if the US Food and Drugs Administration
(FDA) demonstrate that the cosmetic may be harmful to the consumer under customary
conditions of use. The federal Food, Drug, and Cosmetic Act of 1938 with its colour
additive amendment of 1960 and 1962 and the Fair Packaging & Labelling Act of
1966 are the two primary federal laws that regulate the cosmetic industry. The FDA
and the Federal Trade Commission enforce these laws, and two industry-sponsored
groups review the safety of cosmetic ingredients.
In the European Community (EC), cosmetic products are regulated by the council directive
76/768/EEC of 1976, which has been subsequently amended and adapted numerous times.
The Commission of the European Communities to examine the scientific and technical
issues concerning cosmetic regulations established a scientific committee on Cosmetology
The new Dangerous Preparations Directive (DPD, 1999/45/EC) introduces a special
labelling requirement for skin sensitizers in products that are regulated under
this Directive. The packaging of products containing 0.1% of a sensitizer must bear
the inscription Contains name of sensitizer. May produce an allergic
reaction. The aim is to protect individuals already sensitized by providing
information, which enables them to avoid products containing ingredients, which
may elicit their allergy
In Japan cosmetics are regulated by the Pharmaceutical Affairs Law, which is implemented
by the Ministry of Health & Welfare.
In New Zealand Product Safety Standards are regulations made under section 29 of
the Fair Trading Act 1986. The purpose of these regulations is to prevent or reduce
the risk of injury to any person. At the present time cosmetics are not included
under the Product safety standard. From verbal communication with Medsafe &
Consumer Affairs, there is no proposal for cosmetic labelling in New Zealand at
Manufacturers of cosmetics use various terms to sell their products to allergy-prone
people. In NZ there are no standards that govern the use of these terms. Some of
the terms misused include:
Hypoallergenic usually means that the manufacturer believes that
this product is less likely to cause an allergic reaction than others. There is
no requirement to substantiate their claim.
Fragrance free or unscented do not guarantee that the products
do not contain chemicals. They simply imply that they have no perceptible odour.
implies that the ingredients are extracted directly from plants or animal products
as opposed to being produced synthetically. There are an increasing number of natural
ingredients causing allergies.
What can legislation achieve?
In most western countries nickel is the most common contact allergen, and it is
clearly related to body piercing. In 1991 Denmark implemented a statutory order
calling for the reduction in exposure to nickel in nickel-plated items in close
contact to the skin.
In a retrospective analysis, a comparison was made of the number of positive reactions
to nickel seen in private practice of dermatology before and after this statutory
order was implemented. The sensitivity fell from 20.81% pre-1991 to 16.7% in 1999.
A nationwide outbreak of alopecia in USA associated with the use of hair relaxing
(Arch Dermatol.200 Sep; 136(9): 1104-8)
Between 1994 and 1995 a nationwide outbreak of hair loss with scalp injuries involving
tens of thousands of women (and some men) occurred following the marketing of a
chemical hair-relaxing product. Most of those affected reported substantial hair
loss, with a majority indicating growth of new hair that was abnormal in quantity
An epidemic of allergic contact dermatitis due to epilating (hair removal) products
in France & Belgium
(Contact Dermatitis 2002 Aug; 47(2): 67-70)
Over a period of 19 months, 33 cases of acute allergic contact dermatitis from Veet
epilating waxes were observed in France & Belgium.
The lesions started with the legs and spread to other parts of the body, especially
face, and were sometimes so severe that hospitalization was required.
With proper cosmetic legislation (government approval before marketing & proper
labelling) epidemics like those mentioned above can be prevented or quickly curtailed.
Prevalence of Cosmetic Allergy
Prevalence of Cosmetic allergy in the general population is unknown. This is because
most mild reactions occurring at home following use of a single cosmetic product
will be self-diagnosed & often self-treated with OTC medication. In my practice
the majority of the cases of cosmetic allergy that I see come following multiple
hair treatments at the same time (colouring, perming, shampooing & conditioning
with some new & expensive product). Also, individuals who use several skin care
products will have difficulty working out which one is the culprit.
Several studies suggest that about 10% of the adult USA & European population
may suffer adverse reaction to cosmetics
. Several patch
test clinics show ~30% of their patients will have allergic contact dermatitis
In Belgium 36.3% of patients Patch tested for allergic contact dermatitis had an
allergy to 1 or more cosmetic. What is even more worrying is that 48.6% of the children
patch tested showed an allergic contact dermatitis and cosmetic was the number one
In countries where reliable patch tests studies are done (Denmark, Singapore &
USA), for 2 decades, the incidence of allergic contact dermatitis has been rising;
two main reasons can be put forward: rising product consumption and a more exhaustive
allergen research in patch testing.
In New Zealand Patch Testing is not practiced by all Specialists treating patients
with dermatitis / eczema, therefore the true prevalence of cosmetic
allergy in the community is even less reliable.
Problems associated with cosmetics and skin care products:
- Contact Urticaria & rarely contact Anaphylaxis
- Irritant Contact dermatitis
- Allergic Contact dermatitis
Contact Urticaria & Anaphylaxis (Contact Urticaria Syndrome)
Contact urticaria reactions appear within minutes to about 1 hour after exposure
of the urticariant (allergen) to the skin. The patient may complain of a local burning
sensation, tingling, or itching. Swelling and redness may be seen (wheal and flare).
In some cases, this exposure may include the application of cosmetic products, especially
to the face (cosmetic intolerance syndrome).
Cosmetic Intolerance Syndrome
This is a particularly difficult group of patients who complain of severe facial
burning & discomfort with or without any obvious facial inflammation (redness,
swelling etc). These individuals are no longer able to tolerate the use of any cosmetics.
The cause of this entity is multifactorial, and includes:
- Irritant & Allergic contact dermatitis
- Contact Urticaria
- Photoallergic contact dermatitis
- Atopic Dermatitis
- Seborrhoeic dermatitis
- Significant psychological disorder
Contact urticaria is caused by a number of cosmetic ingredients including fragrances,
preservatives, and particularly ammonium persulfate in hair bleaches.
Systemic Anaphylactic reactions to hair dye have been reported.
This is however a very rare cause of anaphylaxis. In the literature there are 2
good reports of fatality from anaphylaxis due to hair dye.
The death from Birmingham in 2001 was a 39 year-old asthmatic lady who had used
the hair dye every two months, but the last time she developed an irritation of
the scalp. She took some antihistamines, which alleviated the symptoms and made
the decision to change the brand of her hair dye. She died within an hour of applying
the dye to her hair. The inquest was told that the product contained colourant and
a separate developer (like all the other permanent dye systems), which must be mixed
together. This company recommended that a small amount of the colourant should be
tested on the arm 48 hours before being applied to the head. Six other leading companies
in the industry recommend that users test the entire product including the developer.
Staging of CUS
Skin reactions only (Stage 1 & 2)
Stage 1 – Localized urticaria (redness & swelling), non-specific symptoms
(tingling, itching & burning)
Stage 2 – Generalized urticaria
Extracutaneous reactions (Stage 3 & 4)
Stage 3 – Bronchial asthma (wheezing), Rhinitis (sneezing, runny, itchy nose),
difficulty swallowing, nausea, vomiting, diarrhoea
Stage 4 – Anaphylactic shock
Contact dermatitis is simply inflammation that results from the
interaction of skin and an external substance (even water) that comes in contact
with it. It is an altered state of skin reactivity induced by exposure to an
. For the vast majority of people, these substances are
harmless. Eczema and dermatitis are often used synonymously
to denote a polymorphic pattern of inflammation of the skin. In all cases the lesions
of contact dermatitis are primarily confined to the site of contact. Contact dermatitis
can look – and itch – very much like eczema. It usually presents as
a rash of tiny blisters, inflamed reddened skin, sometimes dry, or sometimes moist
Contact dermatitis is produced through one of two major pathways: irritant or allergic.
Irritant contact dermatitis (ICD) and allergic contact dermatitis
(ACD) are two of the most common dermatologic conditions in industrialized societies,
with a prevalence of up to 10%. The two conditions are clinically indistinguishable
and often both conditions co-exist. Many of the allergens causing ACD are also irritants.
Irritant contact dermatitis predominates, accounting for 80% of
all cases of contact dermatitis. ICD is a non-immunologic skin reaction that does
not involve immune system sensitization (previous exposure to the allergen). It
can occur in all members of the population depending on the "irritancy"
of the chemical, the duration of contact and individual susceptibility. Atopics
(who invariably have dry skin) are more prone to irritant dermatitis. Water is one
of the most common irritants; therefore atopics who do a lot of wet work will often
get irritant hand dermatitis. Another reason atopics get irritant dermatitis is
that the skin gets injured from chronic scratching, allowing the otherwise harmless
chemicals in cosmetics to enter the skin. The most common skin irritants include
acids, alkalis, detergents, and solvents that disrupt the barrier function of the
skin. Common cosmetics / skin care products causing skin irritation include:
- Bath soaps & shampoos
- Eye shadow & mascara
- Make-up removers
- Permanent hair-waving solutions.
Water present in cosmetics and skin care products is the most common irritant to
very dry skin.
Irritant contact dermatitis is a risk factor for allergic contact dermatitis, as
the penetration of contact allergens is enhanced when the skin barrier function
Allergic contact dermatitis (ACD), on the other hand, is an immunologic
skin reaction that occurs in a genetically predisposed individual. The allergic
response occurs only when a persons immune system is sensitized to the allergen.
The more contact the individual has with the allergen the greater the risk of sensitization.
In sensitized individuals, allergic contact dermatitis appears or is exacerbated
24 to 96 hours after contact with the causative allergen. ACD is usually accompanied
by intense itching. The edges of the lesions are usually well demarcated, but unlike
irritant dermatitis it may propagate beyond the site of contact. This reaction is
also known as delayed hypersensitivity reaction, since the rash usually develops
more than 12 hours after contact with the allergen. The reaction usually peaks about
48 hours after exposure. The number of chemicals known to be capable of causing
ACD is said to be near 3000 and constantly increasing.
Site of the skin reaction is usually the face especially around
the eyes. In one study allergic contact dermatitis was found to be the cause in
74% of patients with eyelid dermatitis. In Saudi Arabia it is well known that men
with dermatitis in the beard have an allergy to permanent hair dyes.
Common allergens in cosmetics and skin care products that cause contact dermatitis
Current reviews demonstrate that the most frequent allergenic groups causing cosmetic
allergy are fragrances, preservatives, and paraphenylenediamine (PPD) found in permanent
The commonest allergen causing ACD is fragrance. More than 5000 different fragrances
are used in cosmetics and skin care products. Seventy to eighty percent of fragrance
allergy can be picked up by patch testing with Balsam of Peru and Fragrance Mix
(which contains 8 common fragrances). Fragrance can also cause increased pigmentation
of the affected skin, photodermatitis, or contact urticaria.
It is important to know that "unscented" does not mean "fragrance-free".
Some unscented products might contain a fragrance to mask other chemical odours.
To indicate that no fragrance is added to a product it must be marked "fragrance-free"
or "without perfume".
In 1989, less than 10% of the patients patch tested in a multicentre project in
Germany reacted to the fragrance mix (a mixture of 8 important fragrances). Between
1990 and 1994, a steady increase in the percentage of sensitizations diagnosed to
more than 13% was noted
Screening for Fragrance Allergy:
These are the fragrances tested in a standard patch test battery:
- Balsam of Peru
- Oak Moss
- Cinnamic aldehyde
- Cinnamic alcohol
- Alpha amyl cinnamic alcohol
- Isoeugenol &
Musk Ambrette and Moskene
In a worldwide multicenter investigation on fragrance contact dermatitis, reaction
to fragrance mix occurred in 78% of patients patch tested
Balsam of Peru
Balsam of Peru (BP) is usually included in the standard screening patch-test series
as an indicator of fragrance sensitivity. It is positive in 50% of cases of fragrance
allergy. BP is a naturally occurring substance, obtained from fir trees. It is composed
of many allergens including benzyl acetate, benzoyl alcohol, cinnamic acid, cinnamic
alcohol, cinnamic aldehyde, eugenol, and isoeugenol.
Paraphenylenediamine (PPD) Hair dye Allergy
This is the most important dye used for permanent (oxidation) hair colouring and
is the third most common ingredient after fragrances & preservatives that cause
contact dermatitis from cosmetics. Permanent hair dyes are more sensitizing compared
to other types of hair dye.
In most cases the reaction to the dye is itching of the scalp and some redness,
but nothing more. These individuals might just think they have a bit of dandruff.
In more severe cases the hair dye may trigger scaly skin & pain. The distribution
of the affected skin can vary and may not match the exact area to which the dye
was applied. In more severe cases there can be swelling around the eyes and scaly
skin on the ears, face & neck. Sensitization to hair dye may gradually develop
with repeated exposure.
In some European countries, PPD was banned because it was thought to be too hazardous.
The regulations of the EEC, however, have allowed up to 6% PPD in hair dyes.
In the consumer, PPD produces acute dermatitis that involves the scalp, eyelids,
face, and hairline and may extend to include the neck & upper portion of the
trunk, but may spread to involve the whole body. In the hairdresser the most common
region affected is the hand, but other exposed areas like the arms & face may
be affected. Once the dye becomes fully oxidized it is no longer allergenic; thus
dyed hair does not cause dermatitis.
Other damage to the scalp skin can make one more sensitive than normal to hair dye
and other chemicals.
Substances related to PPD which should be avoided in PPD-sensitized people
Benzocaine (found in some haemorrhoid preparations) & procaine local
- Azo dyes: used in temporary & semi-permanent hair dyes, pen inks,
Textiles dyes especially dark clothing & clothing made of synthetic fiber
like polyester or nylon
- Some foods & pharmaceuticals coloured with azo dyes
- Sulfa drugs
- Para-aminobenzoic acid (PABA) found in sunscreens
Hair dye open skin sensitivity Test (Dab test) or Open Patch Test
In many countries there is legislation that requires hair dye products to carry
a warning about conducting patch test prior to using the dye. This is a precaution
to make sure the individual is not sensitized to the dye.
Allergies to PPD can develop, even though there was no reaction during previous
use. For this reason, it is important to take the allergy test
48 hours ahead
of every use
The test area used is either behind the ear or inside the arm at the elbow. A small
amount of the colour base (or some companies recommend mixing the base
with the developer first) is applied to the test area. Do not wash the test area.
Wait 48 hours unless there is reddening, burning or other irritation. If there is
no reaction on the unwashed patch test site after 48 hours, then one can proceed
to the full application.
Three dermatological departments in Italy, Great Britain & Poland, have validated
this test. They considered it an effective method to detect delayed hypersensitivity
(contact allergy) to hair dyes, and as such are useful in the secondary prevention
of hair dye allergy.
Preservatives in cosmetics and skin care products are the second most common cause
of skin reactions. Cosmetics that contain water must contain some preservative to
prevent bacterial or fungal growth. Examples of cosmetics preservatives that cause
- Parabens are the most commonly used preservatives in cosmetics
Formaldehyde is an important sensitiser & is released by a number of biocides,
it is mainly found in shampoos
- Imidazolidinyl urea (Germall 115)
Quaternium-15 (Dowcill 200) is a formaldehyde releasing preservative found in many
cosmetics including, eye makeup, foundations, shampoos, moisturizing lotions, sunscreens,
body powders, and skin cleansers.
- DMDM hydantoin (Glydant)
Cocamidopropyl Betaine (CAPB) was voted Contact Allergen of the year for 2004
by a committee of international experts. It is a non-ionic surfactant found primarily
in rinse off cosmetics (shampoos, soaps, and bath gels). It is less irritating to
the skin than older surfactants. For this reason patients may think that a less
irritating product such as a baby shampoo is safer for the skin when it is more
likely to cause allergic contact dermatitis.
A case was presented in the American Journal of Dermatology (Vol 15, No 1 (March),
2004: pp3-4) of a 37-year-old woman who presented with eyelid dermatitis that had
been present for 5 months. She was instructed by her family doctor to apply baby
shampoo to the eyelids daily (similar advice given in NZ as well). Patch testing
revealed a + reaction to CAPB. CAPB was present in the baby shampoo she applied.
Discontinuation of this product resulted in clearing of her allergic contact dermatitis.
CAPB is found in over 600 personal care products (according to FDA). The case of
CAPB illustrates an important point regarding allergy to cosmetics. Because CAPB
is less irritating than other surfactants, it may be preferred by consumers,
manufacturers, and doctors. The fact that it is more allergenic came to light only
after its widespread use.
The reported prevalence of allergic contact dermatitis (ACD) secondary to CAPB exposure
ranges from 3.0 to 7.2%
Lanoline or Wools alcohol
In North America lanoline was the fourth commonest cosmetic allergen (after fragrance,
preservatives and PPD) causing contact dermatitis
is felt that the prevalence of ACD to lanoline is decreasing because knowledge of
its allergenicity has been known for a very long time.
It is a natural material obtained from the sebum of sheep. It is recovered from
raw wool by solvent extraction. It is used in cosmetics because of its emollient,
moisturizing, and emulsifying properties.
There are several allergens present in lanoline, and lanoline-sensitive patients
can sometimes tolerate one lanoline preparation but not another.
Cosmetics containing lanoline include:
- Moisturizers, Hand creams, Protective creams
- Glossy lipsticks
- Makeup remover, Eye makeup
- Foundations, eye makeup
- Baby oils & diaper lotions
- Hair spray
Cosmetics with herbal ingredients
Virtually all-herbal remedies have been reported to cause either allergic sensitization
In a recent study in Portland, Oregan, USA, 63% of patients with suspected cosmetics
dermatitis that had used a skin product containing botanical extracts were patch
test positive to a botanical extract. In New Zealand the true prevalence of contact
allergy to botanical extracts in patients with cosmetics dermatitis is unknown,
as most people who suffer from skin rashes do not seek medical help unless the rash
Common herbal products causing contact dermatitis include plants from the Compositae
- Chamomile (found in numerous shampoos & other hair treatment products)
- Daisy (Chrysanthemum)
- Dandelion (Taraxacum)
- Ragweed (Ambrosia)
Several plants in the Compositae plant family are regularly included in "natural
skin care products" in New Zealand, especially shampoos and aromatherapy solutions.
In some cases the reactions to Compositae is worsened by sunlight, often giving
the appearance of a light-sensitive rash.
Tea Tree (Melaleuca alternifolia) Oil is increasingly being used
in NZ in various cosmetics (soaps, deodorants, toothpaste, gargles & aftershave)
and allergic contact dermatitis is being found related to this product throughout
The leaves of the tea tree contain an essential oil, which contains turpentines
(limonene, alpha-pinene, phellandrene). In one study in Honolulu limonene was the
most common allergen causing allergic contact dermatitis from tea tree oil.
The 'tea tree' oil available in the Netherlands is distilled from the Melaleuca
alternifolia and mainly contains eucalyptol. Eucalyptol is probably the most important
allergen. The Photoaged Melaleuca is a stronger sensitiser than regular tea tree.
There have been recent reports of topical tea tree oil causing anaphylaxis (Allergy
Asthma Proc. 2003 Jan-Feb; 24(1): 73-5)
There are reports in the literature describing several individual cases of contact
dermatitis in patients using propolis as a component of various cosmetic products,
listing the most frequently sensitizing constituents of propolis. There are also
reports of the existence of a cross-reaction between the components of Peruvian
balsam and propolis constituents.
With the vigorous back-to-nature trend in Western countries, henna as a natural
hair dye has become increasingly popular. This shift away from chemical dyes is
enforced by the relatively high risk of sensitization to chemical dyes, in both
hairdresser and their clients.
Henna is derived from a shrub Lawsonia inermis, which is native to the Middle East
& North Africa.
There have been several reports in the literature of Immediate Allergic (& Anaphylactic)
reaction to using Henna hair dyes. Most cases had sneezing, runny nose, cough, &
shortness of breath instead of skin reactions. They were all diagnosed with the
help of a positive skin prick test to henna extract. Most of these individuals were
hairdressers who became sensitized from their work. It is felt that they became
sensitized by inhalation of henna powder dispersed in the air.
Henna also causes allergic contact dermatitis.
Photosensitivity is the term used to describe skin disease caused
by the interaction of UV radiation and an exogenously (externally) acquired chemical
agent, which may be either a drug or food taken orally, or a substance applied to
the skin. It can be divided into photodermatitis, also referred to as photoallergic
dermatitis, and photoirritant contact dermatitis.
Plants that cause photodermatitis (Phytophotodermatitis)
Phytophotodermatitis produces reddening and blisters on first exposure
followed by persistent hyperpigmentation (darkening of the skin). This darkening
of the skin can last for months. The rash is produced via a phototoxic reaction,
which simply means that the reaction renders the skin susceptible to damage by UV
light, and symptoms include burning pain at the affected site. This is in contrast
to the reaction produced by plants such as poison ivy, which is classified as allergic
contact dermatitis, and involves symptoms such as intense itching.
Compounds related to furocouramins (psoralens) usually cause plant-related photosensitivity.
Two requisites for initiation of phytophotodermatitis are contact with a sensitizing
plant (e.g. furocouramin) and exposure to ultraviolet light (wavelength greater
than 320 nm), usually sunlight. Therefore, this dermatitis is usually seasonal.
Common plants causing photodermatitis:
In New Zealand many of these plants are also being added to "natural skin care
Contact urticaria is a hives-like reaction occurring at the site
of contact of the skin product and usually occurring within 15 minutes of the product
touching the skin.
Diagnosis of skin rashes caused by cosmetics
Contact Urticaria is diagnosed by applying the product to the skin
for 15 – 20 minutes and observing the skin for redness, swelling and itching
or doing a skin prick test (applying the suspected allergen/s to
the forearm and pricking the skin with a lancet & waiting 15 minutes for a bump
like a mosquito bite at the site of the prick)
Contact Dermatitis is diagnosed by doing a patch test.
The only way to obtain proof of allergic contact dermatitis is by patch testing.
Patch testing is the universally accepted method for the detection of the causative
contact allergens. The positive patch test reproduces an experimental contact dermatitis
on a limited area of the skin. This is different from skin prick testing (which
gives a positive response in 15 minutes) in that it is a delayed hypersensitivity
response (it gives a positive response in about 48 hours).
The most frequently encountered contact allergens have been selected by various
international contact dermatitis groups and included in standard patch test series.
The chemicals are taped to the back in small chambers. The skin is not broken. The
patches stay in place for 48 hours. You cannot shower or do any work or exercise
that will wet or loosen the patches.
After 2 days, the patches are removed, and a reading is done. The patch sites are
marked, and you may be asked to return for a final reading on another day. An experienced
doctor can differentiate between allergic contact dermatitis and an irritant reaction
on patch testing.
Repeated Open Application Test (ROAT) or Use Test
This is a simple test for new skin care products or products suspected of causing
skin reactions. A small amount of the product is applied twice daily to a small
area of normal skin, usually on the front of the elbow for 1 week. If no rash appears
after 1 week the product is considered safe for that individual. This test simulates
the everyday use of cosmetic products and can be used to define the clinical relevance
of doubtful or positive diagnostic patch tests.
Photo-patch testing is patch testing with the addition of radiation
to induce the formation of photoantigens. All photosensitive patients should be
Cosmetic Allergy & The Future
A recent Patch test study done in Austria (published in Paediatrics Dermatology
2003 Mar-Apr; 20(2): 119-23) showed that the overall sensitization rate was highest
in children less than 10 years old (62%) and decreased steadily to be lowest among
patients more than 70 years old. This coupled with the fact that appearance is so
important to adolescents as they are bombarded with numerous cosmetic advertisements;
they are significant consumers of toiletry & skin care products. Therefore we
would expect the prevalence of cosmetic allergy to continue to increase.
(1) Allergic contact dermatitis to topical minoxidil solution: Etiology and treatment.
J Am Acad Dermatol 2002; 46:309-12
(2) Dooms-Goossens A et al., Cosmetic products and their allergens. Eur J Dermatol
1992; 2: 465-8
(3) Kohl, et al, Allergic contact dermatitis from cosmetics. Retrospective analysis
of 819 patch-tested patients. Dermatology. 2002; 204(4): 334-7
(4) Wolfgang Uter et al. Epidemiology of contact dermatitis. The information network
of Departments of Dermatology. European Journal of Dermatology. Vol 8. Number 1.
36-40 Jan Feb 1998
(5) Maya Krasteva et al. Contact Sensitivity to hair dyes can be detected by consumer
open test. European Journal of derm. Vol. 12. Number 4, 322-6
(6) Joseph F. Fowler Jr et al. Allergy to Cocamidopropyl Betaine and Amidoamine
in North America. Dermatitis, Vil 15, No 1 March, 2004: pp5-6
(7) Adams et al. A five year study of cosmetic reactions, J Am Acad Dermatol 13:
Contact & Occupational Dermatology by James G. Marks & Vincent A. DeLeo