Gonorrhoea is a bacteria which grows in warm, moist areas of the body and is transmitted through unprotected sex Getty

Gonorrhoea could soon become resistant to all forms of treatment, England's chief medical officer has warned, as she urged doctors to take care they prescribe the correct medication. Dame Sally Davies has written to all GPs and pharmacists in the UK to caution that the STD is increasingly able to shrug off azithromycin – one of the major drugs used to treat it.

In her letter, the chief medical officer said: "Gonorrhoea is at risk of becoming an untreatable disease due to the continuing emergence of antimicrobial resistance." Co-signed by chief pharmaceutical officer Dr Keith Ridge, the letter adds: "Gonorrhoea has rapidly acquired resistance to new antibiotics, leaving few alternatives to the current recommendations. It is therefore extremely important that suboptimal treatment does not occur."

Sexual health doctors have seen gonorrhoea "rapidly" develop resistance to traditional treatments in recent years. This resistance made headlines earlier in the year when a strain of so-called "super gonorrhoea" hit Leeds University students in March before spreading throughout northern England.

The super gonorrhoea strain was identified as having a particularly high resistance to azithromycin pills, which are traditionally used alongside an injection of ceftriaxone to combat the STD. Its resistance has been blamed on pharmacists and doctors increasingly treating the STD with just azithromycin tablets while skipping the more expensive ceftriaxone injection.

Not only is this approach not the most effective way to treat gonorrhoea, it also makes it easier for the STD to mutate into a treatment-resistant strain. Earlier this year, the British Association for Sexual Health and HIV advised against prescribing just oral medication for exactly this reason.

What is gonorrhoea and what are the symptoms?

Gonorrhoea is currently England's second most common STD, although the rate of cases is rising so rapidly that it could soon overtake chlamydia. For example, gonorrhoea infections rose by a staggering 19% in just one year recently, up from 29,419 cases in 2013 to 34,958 in 2014.

The STD can be spread by unprotected vaginal, oral and anal sex and if left untreated can cause infertility and pelvic inflammatory disease. Pregnant mothers can also pass it on to their babies.

The symptoms of gonorrhoea can be particularly nasty, with both men and women seeing a thick green or yellow discharge from the genitals and extreme pain while urinating, while women may also experience vaginal bleeding between periods. In some people the illness has no symptoms, however, meaning a person may not know they are infected while unwittingly passing the STD on.