VIRGINIA BEACH, Va. — Thousands of sailors with a medical condition will no longer be allowed to have beards.

The Navy stopped issuing permanent exemptions on Friday that permitted some sailors not to shave.

The shaving-related condition is known as Pseudofolliculitis Barbae, or PFB. It occurs when tightly curled beard hairs are sharpened by shaving, causing them to curve back and re-enter the skin, which can produce facial inflammation, bumps and infections.

But beards can interfere with the seal of protective breathing devices, such as respirators — which can result in serious injury or death.

“Retention of every sailor continues to be a top Navy priority, particularly now when the size of the force is growing. This revision was written in that light with our emphasis on safety of our sailors and medically treating a condition,” Rear Adm. Jeffrey Jablon, director of the Navy’s personnel plans and policy division, told reporters on a conference call.

“If not done, the risk to mission and force is unacceptable.”

The Navy said it will continue to allow sailors to have mustaches because they don’t interfere with breathing devices.

Sailors currently experiencing facial irritation after shaving will be referred to a medical provider for evaluation and possible treatment, according to a Navy statement. Sailors previously issued a permanent shaving waiver must obtain a medical re-evaluation and start a new treatment regimen within six months.

That treatment could involve a special cream that softens beards before shaving and laser hair removal that thins out hairs over the long term.

About 6,000 sailors across the fleet have been diagnosed with PFB, which is a chronic condition. That’s more than the size of the crew of an aircraft carrier, but only a small fraction of the Navy’s 307,000 active-duty sailors.

The Navy said the cream sailors will use costs about $30 per month, although most sailors can make a tube last longer than 30 days.

Commanding officers will still have some discretion to allow facial hair. For example, sailors at sea unable to receive medical treatment may be allowed to keep their beards.