"He [Pietersen] was seen by a wound care specialist yesterday and will receive a course of antibiotics in order to exclude infection," an ECB statement read.
"Medical advice is that a complication can occur post surgery and in this case resulted despite Kevin closely following specialist advice on management of the wound."
The 29-year-old right-hander was ruled out of the remainder of the Ashes series following surgery after the second Test against Australia.
"He will be reassessed by the specialist later this week and will return to his planned programme of rehabilitation once the wound has fully healed," the statement added. His absence in England's Ashes side has coincided with some poor batting performances and the series is now tied at 1-1 with one match remaining at the Oval starting on August 20.
The South African-born Pietersen, who averages 49.96 from 54 Tests, has scored 4,647 runs including 16 centuries since making his debut against Australia in 2005.
Once the Test series is over, England play Australia in a one-off Twenty20 international on September 1 followed by a seven-match one-day international series starting on September 4.
They then travel to South Africa to compete in the Champions Trophy starting with a match against Sri Lanka on September 25.
Photograph: Reuters