Pol Dominguez, 11, is enjoying his summer holidays in Spain. But unlike most children his age, he does not spend his days at the beach or pool, instead staying indoors to avoid ultraviolet radiation that could be deadly for him.

Dominguez has Xeroderma Pigmentosum (XP), a rare disease that affects his skin and eyes. Patients are unable to repair their DNA from solar damage, which puts them at high risk of developing cancer.

His case is extreme: even brief exposure to sunlight causes serious burns.

As heatwaves become more frequent and intense and spread across seasons due to climate change, the risks to Pol and others like him increase.

"The more hours of sunshine, the more solar damage. Therefore more illness," said Asuncion Vicente, a peadiatric dermatologist at Barcelona's Sant Joan de Deu hospital.

With only 2.3 cases per million live births in Western Europe - and around 100 people living with XP in Spain - the hereditary disease is usually detected early when burns appear.

Dominguez and his family, who live in Barcelona, have radically modified their habits to avoid exposure to UV radiation.

To avoid severe sunburns and blistering, Dominguez wears a hood, jacket, sunglasses and gloves outside, even in winter.

In summer, he stays indoors as much as possible, but when he does need to leave the house, the protective clothing is hot and uncomfortable.

Dominguez' school has adapted windows and lights so he can have as normal a life as possible, although he needs to bundle up for outside activities and carries a UV meter to check that an environment is safe.

Dominguez' home is UV-light-proof, with protective film on windows, blinds lowered and fans to keep the environment well-ventilated, said his mother, Xenia Aranda.

When the sun sets, Pol can finally go to the playground without protective gear. Just eating an ice cream outside or turning brings a smile of delight to his face.