Changes in the skin are usually the earliest sign of PXE and lead to the definitive diagnosis. Although the signs of PXE and the age of onset vary considerably, many people first notice an unusual appearance of their skin, usually on the sides or back of the neck. Small bumps or lesions, called papules, may appear. These have been described as looking like a rash or like an unwashed neck. Usually, a small biopsy of a lesion is taken to confirm the diagnosis of PXE. The biopsy requires a very small piece of skin, the size of a pencil eraser, be taken from the neck, underarm and/or inside the elbow. The biopsy is sent to a laboratory where a special stain, the von Kossa stain, is used to detect calcium in the tissue.
For other people, changes in the eye are the first noticeable sign of PXE. Early changes in the eye are visible only during an ophthalmologic examination. Later symptoms can include loss of central vision. Some people are first diagnosed with PXE when they notice the distortion of their vision.