Test Your Knowledge

Phototherapy may significantly improve and even clear many skin conditions. It may help prevent bacterial infections that stem from certain conditions, such as atopic dermatitis. It may reduce the strength of corticosteroids used to treat many conditions or, in some cases, even eliminate the need for them entirely. For example, when psoriasis is treated with psoralens plus ultraviolet A (PUVA) light, no corticosteroids are used. Phototherapy may also increase light tolerance in patients with photosensitive skin.

It is important for patients to understand the potential hazards of ultraviolet radiation, either from natural sunlight or artificial light.

Short-term risks of ultraviolet radiation include:

• Severe and sometimes painful erythema (redness)
  
  
• Burning of the skin, including:
• • Sunburn reactions
  • Burning or stinging sensations
  • Swelling
  • Blistering
  • Pruritus (itching)
    
    
• Increased frequency of recurrent cold sores

Long-term risks of ultraviolet radiation include:

• Photoaging, including:
• • Changes in skin pigmentation
  • Loss of skin elasticity
  • Wrinkle formation
    
    
• Development of cancer, including:
• • Basal or squamous cell carcinoma
  • Cancer of the genitals (particularly in men)

It is important to note that phototherapy can trigger flaring of photosensitivity disorders (e.g., lupus). It can also increase the risk of burning in people taking photosensitivity-causing drugs. 

The medication psoralen given orally is associated with further risks, including nausea, vomiting, fever, general feelings of illness, and cataract formation (condition in which the lens of the eye becomes cloudy). Because psoralens are absorbed by the lens of the eye, patients must wear protective eyewear that blocks 100 percent of ultraviolet radiation for 24 hours after taking psoralens when outdoors, near bright windows or under fluorescent lighting.