The goal of treatment is to protect the patient from sunlight. To this end, regular visits to the dermatologist might be necessary for the purposes of patient education and early detection and treatment of any malignancies.
The use of sunscreens in conjunction with other sun-avoidance methods (eg, protective clothing, hats, eyewear) can minimize UV-induced damage in patients with xeroderma pigmentosum. Sunscreens should be applied to all exposed surfaces (including the hands, the back of the neck, the ears, the lower lips, and the anterior part of the chest) whenever UV exposure is expected. The 2 basic types of sunscreens are physical and chemical.
Physical sunscreens scatter and reflect radiation. They contain large particles, such as titanium dioxide, zinc oxide, red ferric oxide, talc, and kaolin. Physical sunscreens block UV rays, infrared rays, and visible light. Their main disadvantage is that most are opaque, making them less cosmetically acceptable. New advances in physical sunscreens include microfine particles of titanium dioxide or zinc oxide, which are transparent.
Chemical sunscreens absorb UV radiation. Para-amino benzoic acid (PABA) was the first agent developed, but its potential to cause allergic reactions has limited its use. Some agents, such as benzophenones, mainly block UV-A, but they are weak UV-B photoprotectors. Avobenzone (Parsol 1789) has been introduced commercially in the United States. It is a much stronger UV-A photoprotector. Other agents, such as PABA esters, salicylates, and cinnamates, mainly block UV-B. Broad-spectrum chemical sunscreens include a combination of ingredients designed to block both UV-B and UV-A. Many of the new preparations are also designed to be water resistant.
No matter which sunscreen is used, the degree of protection is only partial. The effectiveness of sunscreens is expressed as a sun protection factor (SPF). The SPF is the ratio of the least amount of UV radiation required to produce a minimum erythema reaction with a sunscreen to the amount of the energy required to produce the same erythema without any sunscreen. Usually, sunscreens with a SPF of 15 or greater are recommended.
The Medscape Reference article Sunscreens and Photoprotection provides a detailed discussion of these agents.
Oral retinoids have been shown to decrease the incidence of skin cancer in patients with xeroderma pigmentosum.  This therapy is limited by dose-related irreversible calcification of ligaments and tendons.
Chemical therapy with 5-fluorouracil may be useful for actinic keratoses. Giannotti et al  suggested in a case report that topical treatment with imiquimod and acitretin is an alternative to surgery. They prescribed imiquimod 5% cream to be applied 3 times weekly in combination with oral acitretin (20 mg/d) for 4-6 weeks. No adverse events were reported during treatment, and the tumors had resolved at the 6-month follow-up visit.
A new approach to photoprotection is to repair DNA damage after UV exposure. This can be accomplished by delivery of a DNA repair enzyme into the skin by means of specially engineered liposomes. T4 endonuclease V has been shown to repair cyclobutane pyrimidine dimers resulting from DNA damage. 
Yarosh et al studied in a randomized fashion the effect of topically applied T4 endonuclease V in liposomes in xeroderma pigmentosum patients. Thirty patients were enrolled in this prospective double-blinded study. The annualized rate of new actinic keratoses was 8.2% among the patients assigned T4N5 liposome lotion and 25.9% among those assigned placebo. For basal cell carcinoma, the annualized rates of new lesions were 3.8% in the treatment group and 5.4% in the placebo group. No significant adverse effects were found among any of the patients. The topical application of DNA repair enzymes to the sun-damaged skin of patients with xeroderma pigmentosum lowered the rate of development of 2 forms of these lesions during 1 year of treatment.
Gene therapy for xeroderma pigmentosum is still in a theoretical and experimental stage. Various methods of correcting the defects in xeroderma pigmentosum have been attempted in vitro and in animal studies using viral vectors (adenoviruses and retroviruses) carrying the gene replacement products. Ex vivo skin gene therapy, which refers to grafting skin that has the genetic defect corrected, may be useful in xeroderma pigmentosum in the future.
The malignancies associated with xeroderma pigmentosum should be completely excised.
Consultation with an ophthalmologist is recommended because of the ocular problems associated with xeroderma pigmentosum. The use of UV-absorbing sunglasses should be included as part of the ocular management in patients with this disease. Artificial tears might be used. If corneal opacities supervene, corneal transplants can be performed.
Consultation with a neurologist is also recommended because neurologic abnormalities are seen in 20% of patients with xeroderma pigmentosum.
Multiple cutaneous neoplasms develop at a young age in persons with xeroderma pigmentosum. Death is usually caused by metastatic malignant melanoma or squamous cell carcinoma.
Patients with xeroderma pigmentosum are also susceptible to infection and, in some subtypes, neurologic complications.
Patients should receive follow-up care every 3 months. Follow-up care should be focused on educating the patient and the patient's parents about effective sun protection and early recognition of skin cancer.
Genetic counseling should be offered for families at risk. Antenatal diagnosis is possible by amniocentesis or chorionic villi sampling.
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