Understanding Photosensitivity

Establishing cause of the pigmented skin condition plays a big role in the known effectiveness of any skin lightener, this is the therapists first priority before embarking on a treatment plan. If the established cause of the pigmentation is induced by medication, either topically applied or orally taken i.e. corticosteroids or the contraceptive pill, no guarantee of improvement can be made, until the medication has been discontinued.
There are a number of well known chemicals that aggravate or cause hyper-pigmentation, but research has brought to light products commonly used by skin treatment therapists and clients that also are now known to be photo-sensitisers.

Photoreactions

Chemicals that produce a photoreaction (reaction with exposure to UV light) are called photoreactive agents or, more commonly, photosensitizers. After exposure to UV radiation either from natural sunlight or an artificial source such as tanning booths or even those “purple-lighted” mosquito zappers, these photosensitizers cause chemical changes that increase a person’s sensitivity to light, causing the person to become photosensitized. Medications, food additives, and other products that contain photoreactive agents are called photosensitizing products.
FDA has also reported that photoreactive agents have been found in deodorants, antibacterial soaps, artificial sweeteners, fluorescent brightening agents for cellulose, nylon and wool fibers, naphthalene (mothballs), petroleum products, and in cadmium sulfide, a chemical injected into the skin during tattooing.

Photoallergies

In photoallergic reactions, which generally occur due to medications applied to the skin, UV light may structurally change the drug, causing the skin to produce antibodies. The result is an allergic reaction. Symptoms can appear within 20 seconds after sun exposure, producing eczema-like skin conditions that can spread to nonexposed parts of the body. But sometimes, photoallergic reactions can be delayed. For example, Yuko Kurumaji reported in the October 1991 issue of Contact Dermatitis that photoallergic sensitivity disorders to the topically applied NSAID Suprofen (not approved for use in the United States) took up to three months to develop.

Other regularly used products that can cause photoallergic reactions are cosmetics that contain musk ambrette, sandalwood oil, and bergamot oil; some quinolone antibacterials; and the over-the-counter (OTC) NSAID pain relievers Advil, Nuprin and Motrin (ibuprofen), and Aleve (naproxen sodium).

Phototoxicity

Phototoxic reactions, which do not affect the body’s immune system, are more common than photoallergic reactions. These reactions can occur in response to injected, oral or topically applied medications.
In phototoxic reactions, the drug absorbs energy from UV light and releases the energy into the skin, causing skin cell damage or death. The reaction occurs from within a few minutes to up to several hours after UV light exposure. Though sunburn-like symptoms appear only on the parts of the body exposed to UV radiation, resulting skin damage can persist. Frequently prescribed medications that cause phototoxic reactions include tetracycline antibiotics, NSAIDS, and Cordarone (amiodarone), used to control irregular heartbeats.

Because drug-induced photosensitivity disorder symptoms mimic sunburns, rashes and allergic reactions, many cases go unreported. Also, although research has shown that the numbers of photosensitized individuals may be high, most people do not associate the sun’s light with the development of their skin eruptions.

Who Gets a Reaction?

The degree of photosensitivity varies among individuals. Not everyone who uses medications containing photoreactive agents will have a photoreaction. In fact, a person who has a photoreaction after a single exposure to an agent may not react to the same agent after repeated exposures.
On the other hand, people who are allergic to one chemical may develop photosensitivity to another related chemical to which they would normally not be photosensitive. In such cross-reaction, photosensitivity to one chemical increases a person’s tendency for photosensitivity to a second.

Although those with fair skin are more susceptible to photosensitizing, it is not uncommon for dark-skinned individuals to have chronic photodermatitis.
Photoreactive products can also aggravate existing skin problems like eczema, herpes, psoriasis and acne, and can inflame scar tissue. They can also precipitate or worsen autoimmune diseases, such as lupus erythematosus and rheumatoid arthritis, in which the body’s immune system mistakenly destroys itself.

A Few Common Photosensitizers

These are just a few of the more commonly used drugs that can cause photosensitivity reactions in some people: Brand Name Generic Name Therapeutic Class Motrin ibuprofen NSAID, antiarthritic Crystodigin digitoxin antiarrhythmic Sinequan doxepin antidepressant Cordarone amiodarone antiarrhythmic Bactrim trimethoprim antibiotic Diabinese chlorpropamide antidiabetic (oral) Feldene piroxicam NSAID, antiarthritic Vibramycin doxycycline antibiotic Phenergan promethazine antihistamine

Commonly found and known photo-sensitisers:

• Fragrances or Fragrance fixative or ingredients: Peru balsam, benzoyl alcohol, benzoyl salicylate, canga oil, cinnamic alcohol, geraniol, hydroxycitronellal, mithoxycitronellal, oak moss, musk, xylol, 6-methyl coumarin, cinnamic aldehyde.
• Essential Oils: Jasmine absolute, lavender oil, red zig, sandalwood oil, ylang ylang oil, bergamot, lemon, lime, orange, mandarin, juniper.
• Antiseptics/Disinfectants: Hexachlorophene, bithionol, 5-bromo-4-chlorsalicyanilide, chlorhexidine, chloro-2phenyphenol, triclocaran.
• Sunscreen chemicals: Glyceryl-paminobenzoate, 2-hydroxy-4-methoxy-benophenone, isoamyl-p-N, Ndimethylaminobenzoate, p-methoxy-isoamyl-cinnamate,
• Systemic drugs: Tiaprofenic acid, carprofen, promethazine, chloropromazine.
• Acne medication: Benzoyl peroxide, retinoic acid, unbuffered and very low or high pH glycolic acid, tretinoin, resorcinol.
• Prescription drugs known to temporarily reduce burn time when taken: Antibiotics, anti-fungal, ani-inflammatory agents some blood pressure medication.

It’s a good idea to a have a selection of reference books on drugs and the known side effects of prescription medications. A cosmetic chemistry dictionary and perhaps do a post graduate course in cosmetic chemistry to stay up to date with modern day formulations and actives.

Golden Rule: Establish cause of a pigmented skin condition before deciding the treatment strategy.

Common causes are:

• Physical trauma
• Chemical trauma
• Contraceptive pill
• Pregnancy
• UVR (always)
• Adrenal stress
• Medications like Chlorpromazine will reduce burn time.