Test Your Knowledge

Many skin conditions can be treated with phototherapy, including:

• Pruritus (itchiness). Phototherapy may be beneficial in many different forms of pruritus, particularly those associated with diabetes, liver disorders, uremic pruritus (itchiness due to kidney problems), and itchiness without an identifiable cause.
  
  
• Atopic dermatitis. Dermatitis (inflammation of the skin) with intense itching, often due to an allergic reaction. Phototherapy has been used in the treatment of atopic dermatitis for decades. It is most helpful in chronic, moderate cases of the disease and may reduce the need for potent corticosteroids. However, many treatment exposures may be required to control the condition and recurrence rates are high and rapid, requiring frequent maintenance sessions.
  
  
• Seborrheic dermatitis. Dermatitis marked by oily scales, crusty yellow patches and itching. Phototherapy may be very effective in severe cases of seborrheic dermatitis, but flares may occur, requiring further treatment.
  
  

  

• Psoriasis. A skin disease characterized by raised, red patches of skin often covered with silvery scales. Phototherapy is frequently used to help manage many types of psoriasis, although the erythrodermic and pustular varieties may be more difficult to treat. It may be combined with other therapies (e.g., anthralin, vitamin D analogs, retinoids).
  
  
• Vitiligo. Patches of skin lacking pigmentation (color). Phototherapy may cause repigmentation of the skin by stimulating the production of melanocytes. Doses of ultraviolet light must be tended to more carefully than in other disorders because of increased photosensitivity associated with the condition.
  
  
• Generalized lichen planus. A skin condition marked by flat, shiny, violet papules. Phototherapy may provide an effective alternative to corticosteroids in the treatment of generalized lichen planus. Complete remissions may occur, although it may require many sessions and not all patients respond.
  
  
• Alopecia areata. Patches of hair loss. Certain forms of phototherapy (topical or systemic psoralens plus ultraviolet A [PUVA] light) may help to regrow hair. However, the response varies from patient to patient.
  
  
• Urticaria pigmentosa. A skin disease with brownish papules that sting when touched. Phototherapy may relieve the itching and stinging and may flatten and reduce lesions. In many cases, even long-term symptoms (e.g., migraines, flushing) decrease gradually as treatment is continued. Recurrences are common but respond as well to additional treatment as the original lesions.
  
  
• Generalized granuloma annulare. A chronic rash marked by flat, ring-like spots with lighter centers. Phototherapy has been reported to clear the lesions completely, although long-term maintenance may be required to prevent recurrences.
  
  
• Cutaneous graft-versus-host disease (GvHD). A condition in which cells from transplanted tissue of a donor cause an immune system attack on the tissue of the recipient. Phototherapy can improve some types of GvHD. There is some debate as to whether phototherapy may be useful in the prevention of GvHD shortly after transplantation.
  
  
• Cutaneous T-cell lymphoma (mycosis fungoides). A type of cancer marked by skin lesions and eruptions. Phototherapy can be effective in the early stages of this condition. Lesions may be cleared completely and many patients remain in complete remission for months to years. When relapses occur, they tend to respond as well to phototherapy as the initial lesions.
  
  
• Polymorphic light eruption. A condition in which an itchy, burning rash and blisters appear on the skin following sun exposure.