Features on the skin include:
- in the first months of life, skin redness with lines of blisters affect all areas except the face
- as the blisters heal, warty areas occur on the skin of the hands and feet. These usually clear by six months of age
- excessive brown pigmentation occurs in streaks on the body. These fade in adolescence. These give IP its name
- in adulthood pale hairless streaks or patches appear.
Other features include:
- missing, small or misshapen teeth
- alopecia (baldness) or coarse, dull hair
- nail ridging or pitting.
The eyes are often mildly affected. A third of people with IP have a squint. Around 40 per cent have abnormalities of the blood vessels at the back of the eye (retina). Rarely this can lead to retinal scarring and detachment which may cause vision loss, usually in one eye. Screening is advised to avoid this.