Mark Wahlberg has learned he's allergic to 'almost everything' after undergoing a series of tests.

The 49-year-old star shared the allergy news on Instagram on Tuesday, the result of a scratch test, by posting a photo oh his back covered in pen marks and inflamed skin, which indicates his sensitivity to certain substances. The screening is administered by an allergist and reveals the skin's reactions.

"It only took 49 years to realize I’m allergic to almost everything," he captioned the image, which also showed him wearing a blue surgical mask.

The post prompted a response from Chris Pratt, who joked: "I’m no doctor, but based on the inflammation near the puncture marks it looks like you’re allergic to getting poked by needles."

Mario Lopez added, "Same."

Boogie Nights star Wahlberg has been isolating at home with his family in recent months amid the coronavirus pandemic. He has not revealed what prompted the allergy testing session.

Mark's actor nephew Jeff Wahlberg also commented on the news, jokingly asking "what if u foind out u were allergic to wine (sic)," with The Wire star Domenick Lombardozzi writing back: "Please don't let it be the wine (crying with laughter emoji)."