What test can be done to confirm my cosmetic allergy?
Patch testing is a procedure that helps your dermatologist to identity the exact substance that you are allergic to. During the test, pieces of tapes will be plastered on the back for 48 hours. (Fig. 3) You will return at 72 hours and/or one week later to determine if there is any allergic test reaction. You will be tested to specially prepared patch test material and also to your own cosmetic products. After the evaluation, you can then be given appropriate advice as to which substance you must avoid in future.
Can cosmetics cause pimples?
Acne or pimples can occur in patients who may or may not have past history of adolescent pimples. Some cosmetics, e.g. foundation and moisturizer which are left on the skin for long period of time can cause comedones ("blackheads" or "whiteheads") and inflamed pimples to appear. (Fig. 4) Patients with cosmetic induced pimples are treated in the same way, as with all other ordinary pimples, i.e. appropriate creams/gels with or without oral medication, depending on the severity. Patients should preferably stop using any cosmetics till the skin improves. However, if the patient is uncomfortable with the blemishes on the skin during the healing process, they should use oil-free or low oil-content cosmetics.
Hair cosmetics (hair-dyes):
Hair-dye allergy is one of the commonest causes of cosmetic dermatitis in men and women. Some individuals are able to dye their hair initially without any problem, but may suddenly develop an allergy to the dye after repeated dyeing of hair. The face, ears and neck are often affected. (Fig. 5) The substance that often causes an allergy to hair-dye is para-phenylenediamine (PPD). It can be found in almost all brands of permanent hair dyes. Those who are allergic to PPD hair dyes must avoid all synthetic chemical hair dyes. The only suitable substitute here is Henna vegetable dye or metal pigment dyes.
Sunscreens protect our skin from sun damage. However it can also cause skin problems.
Besides being sold commercially as sun-blocking agents, they are also incorporated into numerous cosmetic products, like lipsticks and facial foundation.
Sunscreens can cause irritant contact dermatitis, allergic contact dermatitis and also photo-allergic contact dermatitis. Photo-allergic dermatitis differs from allergic contact dermatitis, as the rash occurs only after the skin comes into direct exposure with the combination of the allergic substance and sunlight. (Fig. 6)
All chemical sunscreens have the potential of causing photo-allergic dermatitis. Physical sunscreen, like titanium dioxide, does not cause this problem.
You should consult a dermatologist for skin patch test if you suspect that you have sunscreen allergy. After the patch test, your dermatologist should be able to advise you on the type of sunscreen that you can use.