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Patients with xeroderma pigmentosum (XP) typically experience severe, skin-blistering sunburns even after minimal sun exposure. These acute sunburns usually last longer than normal, sometimes for several weeks. However, at birth, the skin of most babies with XP appears healthy. The skin tissue deterioration that is characteristic of XP usually first appears between the ages of six months and 2 years. In addition, an early onset of freckling often occurs in children with XP before the age of 2. 

Generally, the disease progresses through three stages:

• First stage. This stage is characterized by widespread erythema (rashes), scaling (shedding of skin) and the appearance of freckles over areas exposed to ultraviolet (UV) radiation, beginning initially on the face. With progression of the disease, these symptoms are exacerbated and appear on the lower legs, neck and sometimes the trunk. Though these features tend to diminish during the winter months with decreased sun exposure, as time passes, these changes become more obvious and permanent.
  
  
• Second stage. This stage is characterized by skin atrophy (thinning) and the appearance of spider veins, as well as blotchy areas of hyperpigmentation and hypopigmentation (discoloration) throughout the skin.
  
  
• Third stage. This stage is the most severe and is marked by the appearance of numerous tumors due to prolonged exposure to UV radiation, including basal cell carcinoma, squamous cell carcinoma and malignant melanoma. Skin cancer may occur as early as age 4 or 5, and is more prevalent on the sun-exposed areas of skin.

In most cases, the eyes of patients with XP are also sensitive to UV radiation. Exposing the eyes to sunlight may be painful (photophobia). In addition, the eyes of XP patients may easily become irritated, bloodshot and clouded following sun exposure. Conjunctivitis (inflammation of the tissue that lines the inside of the eyelid) may occur. As XP progresses, noncancerous and cancerous tumors, which can lead to blindness, may also occur.

In addition, sometimes patients with XP may experience progressive neurological problems (especially individuals with subtypes XPA and XPD), including:

• Developmental (learning) disabilities
• Mental retardation
• Dementia
• Hearing loss that may lead to deafness
• Ataxia (inability to coordinate muscle movements)
• Polyneuropathy (noninflammatory deterioration of the nerves)

Neurological complications may develop during late childhood or adolescence.