Photosensitivity

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On April 27, 2010, The Wall Street Journal's "Sun-Kissed or Sunburned?" discussed photosensitivity with several Skin Cancer Foundation experts. Read on for more about the problem of increased sensitivity to the sun's ultraviolet (UV) radiation.

By Deborah S. Sarnoff, MD, Ritu Saini, MD, and Andrew Handel

Today, the general public knows more about sun damage and sun protection than ever before. However, not that many people are aware of a phenomenon that can accelerate and exacerbate sun damage, making the need for caution outdoors even more urgent. This phenomenon is called photosensitivity - an abnormally increased skin sensitivity to the sun's ultraviolet rays (UVR) brought on by certain medications and medical conditions.

A person who is photosensitive may experience some form of dermatitis, a skin rash caused by an allergy to or physical contact with a particular substance, in this case UVR. The face, outer arms, and upper chest are the most common areas for a rash due to photosensitivity.

The reaction may be either photoallergic or (more commonly) phototoxic, often in response to a specific medication. A phototoxic reaction typically shows up as an exaggerated sunburn, usually occurring within 24 hours of sun exposure. Photoallergic reactions, however, do not occur until one to three days after the substance has come into contact with the body, since they require activation of the immune system to mount the response. Photoallergy, like other allergies, tends to occur in previously sensitized individuals; repeat exposure to the same allergen plus UVR exposure can prompt a typical pruritic (itching) and eczematous reaction (red bumps, scaling, and oozing lesions, as in eczema).

DISORDER-INDUCED PHOTOSENSITIVITY

A number of medical conditions can lead to photosensitivity:

CONNECTIVE TISSUE DISEASES

LUPUS ERYTHEMATOSUS (LUPUS)
Lupus erythematosus (LE) is a chronic inflammatory connective tissue disease most commonly affecting females 20 - 50 years old. It is characterized by photosensitivity but may also be associated with internal organ involvement. Lupus-related skin lesions, from red scaly patches and plaques to purple spots and lumps, are most commonly located on sun-exposed areas and may lead to scarring and/or pigment loss as well as hair loss. Patients with certain forms of LE may develop red scaly patches on the back and chest following sun exposure. Scars that form from lesions on the lips must be closely observed, as they may lead to squamous cell carcinoma (SCC). Infants of mothers with LE may be born with ring-like lesions of the skin and develop heart rhythm problems (called "heart block").

Certain medications, such as minocycline, hydralazine, carbamazepine, lithium, sulphonamides and phenytoin, may in rare instances play a part in triggering LE, and when these are discontinued, the disease usually remits. Drug-induced lupus does not usually affect the skin, but if it does, oral and topical steroids, corticosteroids, calcineurin inhibitors, antimalarial tablets, and laser surgery can all help to minimize scarring and reduce the size of lesions.

DERMATOMYOSITIS
Dermatomyositis (DM) is a rare muscle disease that involves the skin. While muscle weakness is the main result of the disease, on sun-exposed areas patients develop skin lesions (often reddish or bluish-purple patches), telengiectasias (broken blood vessels), hyperpigmentation (skin darkening) and/or hypopigmentation (loss of skin pigment). Hydroxychloroquine, an antimalarial, may be prescribed to reduce skin outbreaks caused by photosensitivity.

PHOTOSENSITIVITY-SPECIFIC DISORDERS

ACTINIC PRURIGO
Actinic prurigo is a disorder beginning in the first decade of life, mainly in darker-skinned individuals such as Native Americans and those of Mexican, Central American and South American descent. It is characterized by red itchy bumps that evolve into scaly patches due to sunlight exposure. In contrast to other photosensitivity disorders, actinic prurigo can persist year-round, with lesions appearing even in winter. Liberal use of sunscreens and sun-protective clothing is helpful, but complete sun avoidance may be the only fully effective means of prevention.

CHRONIC ACTINIC DERMATITIS
Chronic actinic dermatitis (CAD), a disorder predominantly seen in elderly males, is characterized by itchy red, inflamed bumps, and scaly patches that develop on sun-exposed skin, especially on the scalp, face, back of the hands, and upper chest. It encompasses several related disorders and often stems from an allergic reaction that leads to persistent photosensitivity. Outbreaks become most severe during the summer months when the body is exposed to the greatest amount of UVR. Effective treatment requires strict avoidance of UVR.

POLYMORPHOUS LIGHT ERUPTION
Polymorphous Light Eruption (PMLE) is a photosensitivity disorder most commonly manifesting before age 30, the majority of time in women. An itchy rash consisting of pink bumps appears on sun-exposed areas of the body, its initial onset generally in spring (when the individual is first exposed to the sun). However, the condition typically improves with continued sun exposure and increased UV tolerance, so that by summer's end it is no longer a problem.

SOLAR URTICARIA
Solar urticaria is a rare disorder that usually affects females between 20 and 40 years of age. Red and swollen itchy hives develop upon exposure to sunlight, appearing as quickly as five to 10 minutes after UV exposure but generally subsiding within a few hours. Associated systemic symptoms, including headaches, nausea, breathing problems and dizziness, may occur.

XERODERMA PIGMENTOSUM
Xeroderma Pigmentosum is a rare but well-known disorder involving dangerous photosensitivity. An inherited condition with many variations, it can lead to the thinning and fragility of sun-exposed skin, telangiectasias, and ultimately a high risk of developing both melanomas and nonmelanoma skin cancers. Total sun avoidance is essential with this condition.

A variety of other conditions may involve photosensitivity as well, including: actinic folliculitis; the inherited disorders Bloom syndrome, Darier's disease and Rothmund-Thompson's syndrome; disseminated superficial actinic porokeratosis (DSAP); hydroa vacciniforme, which mainly affects children; lichen planus actinicus; pellagra; pemphigus erythematosus, and pseudoporphyria. All are quite rare but call for heightened sun protection.

CHEMICAL-INDUCED PHOTOSENSITIVITY

Phototoxicity and photoallergy can result when someone uses one or another of a wide range of photosensitizing products and is then exposed to UVR. These products can include both prescription and OTC (over-the-counter) medicines. Some of the most common photosensitizing agents are antibiotics such as the tetracyclines and ciprofloxacin; nonsteroidal anti-inflammatories (NSAIDs) such as ibuprofen; diuretics; and retinoids. For some individuals, even certain sunscreens can cause a problem; changing sunscreens is advisable for them. [See Table below.]

MEDICATIONS ASSOCIATED WITH PHOTOSENSITIVITY
The following table provides a brief overview of the most common prescription and OTC products that can trigger photosensitivity.
GENERIC NAME BRAND NAMES TYPE OF DRUG COMMENTS
Amiodarone Cordarone Antiarrhythmic (used to correct irregular heartbeat) Blue-gray discoloration develops on sun-exposed areas.
Quinidine Quinidex Antiarrhythmic  
Ciprofloxacin Cipro XR and Proquin XR Antibiotic (fluoroquinolones) Most commonly used to treat urinary tract infections and complicated skin infections. It has many interactions with other medications.
Co-trimoxazole Bactrim, Septra, and Sulfatrim Antibiotic (Trimethoprim- Sulfamethoxazole) Used to treat urinary and respiratory tract infections.
Dapsone Aczone Antibiotic (sulfone) Used to treat leprosy, dermatitis herpetiformis, and other skin conditions. The rash from photosensitivity may occasionally be severe enough to warrant medical attention.
Tetracyclines, including doxycycline and minocycline Minocin, dynacin, adoxa, doryx, vibra-tabs Antibiotic Minocycline can result in muddy brown discoloration on sun-exposed areas.
Griseofulvin Fulvicin, Grifulvin, and Gris-PEG Antifungal Indicated for fungal infections.
Furosemide Delone, Detue, Lasix Anti-hypertensive Diuretic for high blood pressure.
Hydrochlorothiazide Microzide Anti-hypertensive Diuretic also used for prevention and treatment of kidney stones.
St. John's Wort   Herbal treatment Used to alleviate mental illnesses, depression, anxiety and sleep disorders.
Ibuprofen Advil, Motrin, and Nuprin NSAID (non-steroidal anti-inflammatory) Used to treat headaches, muscle aches, other pain, fever and inflammation.
Ketoprofen Orudis NSAID  
Naproxen Aleve, Anaprox, Naprosyn NSAID Relieves discomfort and pain caused by many forms of arthritis, including rheumatoid, juvenile, ankylosing spondylitis and osteoarthritis, as well as tendonitis and gout. Most common cause of pseudoporphyria.
Chlorpromazine Thorazine and Chlorpromazine Hydrochloride Intensol Anti-psychotic (phenothiazines) Can even cause photosensitivity in pharmacists who handle the medication. Sun-exposed areas can develop slate-gray discoloration.
Acitretin Soriatane Oral Retinoid Used to treat many skin conditions including psoriasis and Darier's disease. Also used for chemoprevention of skin cancers in transplant patients.
Isotretinoin Accutane, Amnesteem, Claravis, Sotret Oral Retinoid Used to treat severe nodular and cystic acne.
5-Fluorouracil Carac, Efudex, Fluoroplex Anti-neoplastic Used topically for treatment of skin precancers known as actinic keratoses, as well as superficial basal cell carcinomas (BCCs). It causes the skin to redden and blister, and treated skin often becomes dry and peels away. The skin can become irritated, sting, and can be more likely to develop a sunburn quickly. Orally and intravenously, it is used as a treatment for colon, rectal, stomach, pancreatic and breast cancers, and has also been proven effective in cases involving ovarian, cervical and bladder cancer.
Psoralens   Topical Furocoumarins Used specifically as a photosensitizing agent in the treatment of several skin conditions, including psoriasis.
Coal Tar Denorex, Pentrax, Tegrin Topical keratoplastics A photosensitizing agent useful in conjunction with phototherapy (therapy using UV light) as a treatment for psoriasis, it is less toxic and often less expensive than other drugs used to treat this condition.
5-Aminolevulinic Acid Levulan Kerastick Topical PDT (Photodynamic Therapy) Pro-photosensitizer In conjunction with a light source such as blue light, it is used to treat acne, actinic keratoses, some skin cancers and enlarged oil glands. Redness and swelling are the most common reactions to sunlight after this treatment. Burning, stinging or tingling sensations also occasionally occur in those using PDT.
Tazarotene Tazorac, Avage, Zorac Topical Retinoid Used to treat both acne and effects of photoaging.
Tretinoin Retin-A, Renova Topical Retinoid Also used in the treatment of acne and photoaging.
Sunscreens     Although a key tool in sun protection, sunscreens can cause photoallergic and phototoxic reactions in some. Those containing the commonly used UVB absorbers known as benzophenones are the biggest culprits; other sunscreens should be substituted.
Fragrances     Outbreaks most commonly develop on the face, arms and hands, appearing anywhere between a few minutes and two days following exposure to the allergen and the sun. Musk ambrette and coumarins are common offenders. Allergy to these substances can be determined by patch testing.
 

CONCLUSIONS

Although not exhaustive, our discussion provides an overview of some of the medical conditions and therapeutic agents associated with photosensitivity. In some cases, photosensitivity can be a serious problem: Certain medications, such as the fluoroquinolone antibiotics, have induced benign and malignant skin lesions, including basal and squamous cell carcinomas, in animals. A recent population-based case control study provides evidence that photosensitizing agents can increase skin cancer incidence in humans. With widespread use of some of these agents, and with basal cell carcinoma and squamous cell carcinoma incidence increasing rapidly worldwide - due, above all, to sunlight exposure - counseling becomes ever more important for patients requiring these medications.

Since many of the medications are vital in maintaining or restoring health and quality of life, it is important not to "throw out the baby with the bathwater." Rather than eliminating these treatments, some combination of sun avoidance and sun protection is the preferred strategy to prevent the unwanted effects of photosensitivity. By seeking shade and staying out of direct sunlight between 10 AM and 4 PM (generally the sun's most intense hours); employing high-SPF broad spectrum sunscreens (SPF 30 or higher is advisable for photosensitive individuals); and wearing sun-protective clothing, including wide-brimmed hats and UV-blocking sunglasses, patients can continue to reap the benefits of these medications while avoiding sun damage.

DR. SARNOFF, an Associate Clinical Professor of Dermatology at NYU School of Medicine, is in private practice in Manhattan and Long Island. She is Vice President of the Skin Cancer Foundation, Vice President of CancerCare of Long Island, and currently President of the Long Island Dermatological Society. She coauthored Beauty and the Beam: Your Complete Guide to Cosmetic Laser Surgery and Instant Beauty: Getting Gorgeous on Your Lunch Break.

DR. SAINI completed New York University School of Medicine, where she received her MD degree with honors in Biochemistry. She then went on to train in dermatology at the University of Miami and is currently a Mohs/cosmetic fellow with Dr. Sarnoff and Dr. Perry Robins in Manhattan.

ANDREW HANDEL, an undergraduate at the College of Agriculture and Life Sciences at Cornell University, is a Biology and Society major.

From The Skin Cancer Foundation Journal, vol. 26, 2008, pps 38-41.