Definition

• Psoriasis and eczema are similar conditions, but not the same thing. Both involve outbreaks of dry, scaly and itchy patches on the skin. According to the American Academy of Dermatology (AAD), eczema is a general term for inflammation of the skin, while psoriasis is a hereditary disease linked to a faulty immune system. Though there are many different treatments for both conditions, light therapy has been found effective for sufferers of both conditions.
  
  

Function

• Light therapy works by bathing the immune system in wavelengths of UVA or UVB radiation. This exposure disrupts the immune system, preventing the formation of scaly skin. The exact mechanism is not fully understood, but according to the AAD, light therapy qualifies as an effective treatment for eczema, psoriasis and contact allergies that have similar symptoms. Only affected skin is exposed to the rays, and goggles are worn to protect the eyes.
  
  

Types

• There are two main types of light treatment for ezcema or psoriasis.
  UV light therapy exposes the patient to UVA or UVB radiation, the same type of rays that come from the sun. UVB therapy has been known for more than 80 years, and is one of the oldest and most effective treatments for skin diseases.
  PUVA therapy combines UVA exposure with psoralen, a potent medicine. Patients take psoralen orally or apply it to the skin. The medication makes the skin more sensitive, enhancing the effect of the light treatment.
  
  

Considerations

• While generally effective, light therapy demands a major time commitment from patients. Treatments may take place three to five times per week, and may last for months. Follow-up visits, after the skin has cleared, may take place every week or 10 days on a continuing basis.
  
  

Benefits

• Individual response to treatments for skin conditions like eczema and psoriasis can vary greatly. A treatment that works for one person may fail with another. When it works, light therapy provides several benefits to patients: clearing the skin, preventing infections and reducing the need for other medications.
  
  

Risks

• According to AAD, light therapy can increase a patient's risk for cancer, and may prematurely age the skin. Sensitive skin may darken or burn during therapy. Patients may need to avoid excess sun exposure for several days after treatment, to avoid damage to the skin or eyes.