Chlamydia is a sexually transmitted disease caused by the bacterium Chlamydia trachomatis. It is a common, treatable infection, which often has no symptoms in men or women unless it leads to complications. It is now estimated that chlamydia affects 1 in 12 women between the ages of 16 and 24.

Women

In women chlamydial infection is one of the principal causes of Pelvic inflammatory disease (PID).

Chlamydial infection causes inflammation of:

• The neck of the womb (Cervicitis) - Cervicitis may cause no symptoms, but there may be a vaginal discharge containing pus, and sometimes pain on intercourse, there may also be urinary symptoms, such as frequency and a burning pain on urination. If the condition becomes chronic the cervix becomes swollen and enlarged and may contain cysts that may also become infected. There may be backache, deep pelvic pain, pain on intercourse, and a persistent vaginal discharge.
• The Fallopian tubes (salpingitis), leading to blockage - sexually transmitted chlamydial infection may cause blockage of the fallopian tubes, the tubal blockage prevents the eggs from passing along, or from entering the tube. Partial blockage also increases the risk of pregnancy occurring in the tube (Ectopic pregnancy) Tubal blockage can sometimes be treated effectively by microsurgery.
• The glands that produce sexual lubricant mucus (Bartholinitis) - the opening of a Bartholin gland, situated on either side of the vaginal opening, may become infected and blocked. This will lead to a Bartholin cyst. This is usually painless, but may also become infected, causing a pus-filled Bartholin’s abscess.

Chlamydia can also pass from a mother to baby during childbirth. This may result in eye infection (ophthalmia neonatorum) or lung infection (pneumonitis). Fifteen to 25 per cent of babies exposed at birth develop moderate to severe conjunctivitis 5 to 12 days after birth. Five to 15 per cent develop pneumonitis, usually 4 to 17 weeks after delivery.

Men

In men chlamydia may cause:

• Inflammation of the urine tube (urethritis). Male urethritis is inflammation of the urine outlet tube that runs along the underside of the penis. There is a urethral discharge, yellow pus, mucus and pus or clear mucus at the opening. A complication of untreated urethritis may be a urethral stricture. This is a local narrowing of the bore of the tube. Stricture can seriously interfere with the outflow of urine and can lead to back-pressure effects, which can damage the kidneys.
• Inflammation of the tubular part of the testicle (epididymitis). Epididymitis is inflammation of the tubular structure next to the testicle, the epididymis, as a result of infection, usually secondary to urethritis. It causes the testicle to be hot, swollen and extremely tender, and may lead to the development of a collection of fluid in the area (hydrocele) or even an abscess. Epididymitis may lead to sterility.
• A serious joint and eye disorder (Reiter’s disease). Reiter’s disease is a condition affecting mainly men, and featuring inflammation to the joints (Arthritis), the urethra and often the eyes. The condition occurs one to three weeks after a sexually transmitted chlamydial infection. It is a local inflammation induced in a genetically predisposed person by an infecting agent, in this case the chlamydial germ. Reiter’s disease is the most common cause of arthritis in young men and occurs in about two per cent of men with urethritis.

Genital chlamydial infections are diagnosed by tests done on swab or urine samples.

Testing for chlamydia involves taking a swab from the cervix in women or from a swab put into the urethra in men.

Recently tests have been developed on urine samples, also on swabs women can insert into the vagina and then send for testing.

How is it performed

Genital chlamydial infections are usually successfully treated with antibiotics.  It is important to treat any sexual partners as well.

The complications of long-term infection can be more difficult to deal with. Early diagnosis and treatment will reduce the risk of complications, so possible symptoms should be investigated as soon as possible. Genitourinary medicine (GUM) clinics, or sexual health clinics, can provide the necessary advice, tests and treatment.