Sexually Transmitted Infections

1. General knowledge on sexually transmitted infections and its prevention
2. Common sexually transmitted infections
2.1. Syphilis
2.2. Gonorrhoea
2.3. Non-Gonococcal Urethritis (Male)/Non-specific Genital Infection (Female)
2.4. Genital Herpes
2.5. Genital Warts
2.6. Pubic Lice
2.7. Chlamydia
2.8. HIV infection / Acquired Immune Deficiency Syndrome (AIDS)
3. Sexually transmitted infections and pregnancy



1. General knowledge on sexually transmitted infections and its prevention

Sexually transmitted infection (STI), commonly known as venereal disease, is transmitted through sexual intercourse with an infected sex partner. It can be transmitted through vaginal sex, oral sex and anal sex, but not through social contacts like eating at the same table, travelling in the same public vehicle or swimming in the same pool etc.

Common sexually transmitted infections include Syphilis, Gonorrhoea, Non-Gonococcal Urethritis , Non-Specific Genital Infection, Genital Herpus, Genital Warts, Pubic Lice, Chamydia. Sexual contact is the commonest mode of transmission of HIV infection in Hong Kong.

Sexually transmitted infection is serious as it can affect the genital organ and cause pain and sterility. It can even spread to other organs and cause complications or even death. Offspring of the STI patient may be affected as well.

Sexually transmitted infections vary in terms of latent period. They are not easy to be noticed as the symptoms may not be obvious, infected patients, in particular female ones may show no symptoms at all. Damaged spots in the sex organ, small growth, blisters, itchiness, frequent urination, stabbing pain in the genital organ, excretion of white condensed urethral discharge from male and excretion of greenish-yellow vaginal discharge in female may be symptoms of infection. The patient should seek medical advice as soon as possible to alleviate symptoms and avoid complications.

To achieve the best treatment results, patients with sexually transmitted infections should be patient and obedient to the medical advice given by doctors or nurses. His/her sex partner should receive examination and treatment, if necessary, as well to avoid cross-infection and reinfection. Before recovery, patient should refrain from sex in order to prevent getting other sexually transmitted infections or transmitted to others.

In case a pregnant woman is confirmed to be infected, both she and her fetus will usually be alright if the disease is cured early enough.

As effective immunity against sexually transmitted infections will not be developed in human being, unsafe sexual activities such as having unprotected sex or/and with multiple sex partners, may lead to the same past infections or more than one type of sexually transmitted infections coincidentally.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutually monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

People active in sex should receive regular check-up in order to ensure that they have not contracted STI.

The social hygiene clinics of the Department of Health provide examination, treatment and counselling on sexually transmitted infections. All services are free of charge *and information is kept confidential. Neither advanced booking nor doctor's referral letter is required.

Treatment of sexually transmitted infections is also available from other registered medical practitioners. Self -prescription should be strictly avoided because this would defer the diagnosis of STI and make subsequent treatment more difficult.

*For eligible HK residents who possess relevant document only


2.1. Syphilis

Syphilis is a sexually transmitted infection caused by Treponema Pallidum which carries potentially serious consequences if left untreated.
The incubation period of syphilis varies from 9 to 90 days. Infection can be transmitted by direct sexual contact, from infected mother to her baby during pregnancy and other non-sexual contact methods such as sharing needles. Nowadays, most of the syphilis infected patients are contracted through sexual contact. Patients with untreated syphilis will present different features at different stages..

Primary syphilis:
Most cases present symptoms in 2-4 weeks after exposure. The main symptom is chancre, which is a painless sore on genital area. The sore may be obvious in men, but remain inconspicuous in women if it is situated deep inside the vagina. Even if it is left untreated, the painless sore will heal by itself giving a false impression of cure. However, the treponema will spread throughout the body.

Secondary syphilis:
After the appearance of chancre for 6-8 weeks, infected patients will have wide-spread and symmetrical skin rashes. Palms and soles are commonly involved. Infected patients may have malaise, fever, enlarged lymph nodes, alopecia, mucous membrane lesions or appearance of warty growth change. These symptoms will subside by themselves.

Latent Stage:
Patients are asymptomatic in latent stage syphilis. The disease can only be diagnosed by blood test.

Late syphilis:
Late syphilis may occur a few years to decades after the initial infection. Heart, eyes and central nervous system will be affected resulting in blindness, cardiovascular diseases, neurological and mental illness, physical disability and even death..

A pregnant woman with syphilis may transmit the bacteria to her baby causing congenital syphilis, intrauterine death or other disabilities e.g. blindness and deafness.

Syphilis is curable. It is important to seek early medical advice and treatment if you suspect you have been infected with syphilis or other sexually transmitted infections. The partner(s) should also seek prompt treatment to avoid cross-reciprocal infection. Apart from appropriate drug treatment, follow up to ensure complete recovery is essential. Do not try over-the-counter treatment as it is dangerous to treat yourself without medical advice. Abstinence from sexual activity before full treatment and recovery of yourself and your partner(s) from syphilis is strongly advised.

You may attend the nearby social hygiene clinic for advice, check-up and treatment. Services are provided free of charge*, and all information is kept strictly confidential. You may just walk in. There is no need to book appointment or bring along doctor's referral letter.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.2. Gonorrhoea

Gonorrhoea is a common sexually transmitted infection in Hong Kong. It is caused by Neisseria Gonorrhoeae.

The symptoms and signs will appear after two to five days from infection. and the presentation of disease are different in male and female.

Gonorrhoea in man presents as anterior urethritis. There is purulent urethral discharge associated with pain and frequency of urination.

Gonorrhoea in woman usually affects both the cervix and urethra. The patient may have purulent vaginal discharge associated with irritation and swelling of the genital region. She may also experience burning sensation when passing urine. However, a certain proportion of women have no symptoms.

Unprotected anal sex may lead to rectal gonorrhoea that may cause discharge and irritation from the anus, and pain while passing stool. Unprotected oral sex may lead to pharyngeal gonorrhoea that may cause sore throat. Infection of these sites may however remain asymptomatic.

Gonorrhoea is curable. Apart from appropriate drug treatment, follow up to ensure complete recovery is essential. Due to the recent emergence of drug-resistant strains of gonococci, it is dangerous to treat yourself without medical advice.

If gonorrhoea is not treated, complications may arise. In man, it may cause urethral stricture, prostatitis and epididymo-orchitis. In woman, it may result in bartholinitis, pelvic inflammatory disease, ectopic pregnancy and sterility. The bacteria may be disseminated and cause damage to other structures or organs like the joints. Gonorrhoea in pregnant women may affect the eyes of babies which may lead to blindness.

To stop the spread and prevent complications of gonorrhoea, infected persons should inform their sexual partners about the possibility of infection. The partner needs to seek prompt treatment to avoid cross-reciprocal infection. Refrain from sexual activity is needed until full treatment and recovery from gonorrhoea.

If you suspect suffering from gonorrhoea, please attend the social hygiene clinic of Department of Health for advice and checkup. All services are free of charge *and information is kept strictly confidential. Neither advanced booking nor doctor's referral letter is required.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.3. Non-Gonococcal Urethritis/Non-specific Genital Infection

Non-gonococcal urethritis in man and non-specific genital infection in woman are now the commonest sexually transmitted infection in Hong Kong. In short, it is called NGU and NSGI respectively.

Infected persons usually present with symptoms which are similar to but milder than that of gonorrhoea, such as urethral discharge, frequency and burning sensation during urination. In women, may be asymptomatic.

Complications are similar to that of gonorrhoea such as prostatitis, epididymo-orchitis in man, and salpingitis, sterility, ectopic pregnancy, pelvic inflammatory disease and abortion in woman. It may cause conjunctivitis or pneumonia of the newborn if the mother is infected.

As the infection can be caused by more than one organism e.g. chlamydia trachomatis, which is the commonest causative agent, the treatment regimes and response can be variable among different infected people. Therefore, infected persons should comply with the instruction of the medical personnel with respect to drug therapy and follow-up body checking.

Affected persons should refrain from sexual intercourse before complete cure. The sexual partner should also receive check-up and treatment to prevent cross-reciprocal infection.

If you suspect yourself of having non-gonococcal urethritis, non-specific genital infection, or any sexually transmitted infection, please attend the social hygiene clinic of the Department of Health for advice and checkup. All services are free of charge *and information is kept strictly confidential. Neither advanced booking nor doctor's referral letter is required.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.4. Genital Herpes

Genital Herpes, mainly caused by the Herpes Simplex Viruses Type II (HSV-II), is transmitted through sexual contact. The incubation period averages 2-5 days.

Genital Herpes usually affects the surface of genital area. The affected area has a burning or tingling sensation, followed by the appearance of characteristic grouped small vesicles in pin-pointed to green bean size. These vesicles usually rupture in 3 to 4 days, leaving erosion with translucent fluid. The lesions often heal within 10 days if there is no other infection. Some patients may also suffer from generalised symptoms such as fever, malaise and appearance of lymph glands in the groin.

Infected women may have stinging sensation during urination and the erosion is mostly distributed in inner and outer labia, and around anal region as well. Newborn baby may contract Herpes Simplex virus through the birth canal of the infected mother during parturition, causing disseminated neonatal infection that can lead to multi-organs destruction including the nervous system and eventually death.

There is no treatment that can cure herpes completely. Despite possible herpes relapse, symptoms of herpes relapse are typically milder and shorter in duration than the primary infection of Genital Herpes. The lesions are able to heal in a short period of time. Research findings reveal that antiviral medications cannot completely eradicate herpes to relapse and the likelihood of transmission to partner. In addition, antiviral medications can also cause possible side-effects and drug resistance. Thus, doctor will, according to patient’s condition, prescribe suitable medications for symptom relief. Meanwhile, healthy lifestyle and avoid inducing factors can reduce the chance of herpes relapse.

The followings are common inducing factors:-
-       Psychological stress; depressed mood
-       Malnutrition
-       Impaired genital skin integrity
-       Menstruation
-       Impaired immunity

If you suspect that you have contracted genital herpes you should seek medical treatment and advice. Your sexual partners also need to have check-up. Pregnant women who have a history of genital herpes should inform their doctors during ante-natal check-up. Regular medical check-up and adoption of relevant preventive measures can reduce the chance of transmission to the new born babies.

If you suspect yourself of having genital herpes or other sexually transmitted infections you may attend any of the social hygiene clinics of the Department of Health. All services are free of charge *and information is kept strictly confidential. Neither advanced booking nor doctor's referral letter is required.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutually monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.5. Genital Warts

Genital Warts is caused by Human Papilloma Virus (HPV). It is mainly transmitted through sexual contact. The incubation period may last from several weeks to 8 months. Some may last over one year.

The infected person usually presents with cauliflower-like growths over external genitalia or around the anus. These may then slowly increase in size. The lesions are delicate. They can be traumatized easily and may bleed. Cancers of the genital tract such as cervical carcinoma are linked to certain subtypes of human papilloma virus called "HR-HPV". Although HR-HPV are different from those subtypes that cause genital warts, they share similar mode of transmission and hence may also infect coincidentally those patients with genital warts.

Treatment modalities include topical application of specific medicine, cryotherapy, cautery and surgical excision. It is important to follow medical advice. Personal hygiene is necessary to prevent secondary infection. All sexual contacts of infected person should be examined and treated accordingly.

As there is no definite curative measure, relapse is common and patient should seek advice and treatment if this occurs. As aforementioned, women infected with wart virus are strongly advised to have cervical smear. You may approach your family doctor, gynaecologist, doctors of the woman's health clinics or doctors of the social hygiene clinics for further advice in case of queries.

If you suspect yourself of having genital warts or other sexually transmitted infections you may attend any of the social hygiene clinics of the Department of Health. All services are free of charge *and information is kept strictly confidential. Neither advanced booking nor doctor's referral letter is required.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.6. Pubic Lice

Pubic lice are parasites which, besides affecting the pubic region, may occasionally affect the eye brows, eye lashes, axillae, and the hairy chest region.

Infection is transmitted through close contact during sexual intercourse, or less commonly through direct sexual contact. However, it may also be transmitted through sharing cloths or beddings with affected people.

The lice suck human blood and cause intense itchiness. Secondary bacterial infection may result from scratching. Misuse of drugs can cause skin sensitivity.

Doctor will prescribe appropriate medication according to clinical conditions.  Patients should follow the instructions to complete the treatment. They also need to maintain their under clothings clean and good personal hygiene. Sexual partners should also receive investigations and treatments in order to prevent re-infection (‘Ping Pong’ infection).

If you suspect that you are suffering from pubic lice or other sexually transmitted infections, you should consider attending social hygiene clinic of the Department of Health for check-up, treatment and counselling. All services are free of charge *and information is kept strictly confidential. Neither advanced booking nor doctor's referral letter is required.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.

*For eligible HK residents who possess relevant document only


2.7. Chlamydia

Chlamydia trachomatis is a major sexually transmitted infection in our community. Its usual incubation period ranges from two to four weeks duration.

In male infected with Chlamydia trachomatis, the usual presenting complaints are dysuria and urethral discomfort. If appropriate therapy is not instituted, severe long term complications such as prostatitis, epididymitis and orchitis may result. For female infected with Chlamydia trachomatis, most will remain asymptomatic. This may have profound implications on female patients if they are not properly managed. This includes long term sequelae such as pelvic inflammatory disease, salpingitis and infertility.

Prompt and appropriate drug treatment is effective in treating Chlamydia trachomatis infection and preventing the potential complications.

The most effective way of preventing sexually transmitted infection is to have safer sex and maintain a mutual monogamous relationship with an uninfected partner and avoid casual sex. If this is impossible, condom should be used properly during each sexual contact to reduce the chance of infection.


2.8. Acquired Immune Deficiency Syndrome

AIDS stands for Acquired Immune Deficiency Syndrome. It is caused by a virus called Human Immunodeficiency Virus, HIV. White blood cells are part of the body's defense (immune) system. They normally help the body fight off cancers and infections by germs. The HIV virus attacks and kills certain white blood cells, thus destroying this important defense function. As a result, AIDS patients easily develop infections and cancers which normally do not affect healthy persons. It should be emphasised that there is as yet no known cure for AIDS.

HIV is present in blood, semen, vaginal secretions. A person can be infected by the virus through 3 major routes: (1) sexual contact (2) blood and needles and (3) mother to infant.

(i)Sexual contact: The virus is present in semen and vaginal secretions. The infection can be passed from men to men, men to women and women to men by various forms of sexual contacts, including vaginal intercourse, anal intercourse and oral sex. Anal sex is by far the most risky.

(ii)Blood: HIV thrives in blood. Hence, it can be transmitted by contaminated blood and blood products. Injecting drug users are particularly at risk of contracting HIV through the sharing of unsterilized needles and syringes. HIV may also be transmitted by unsterilized instruments for tattooing, ear-piercing and acupuncture, but the actual chance of getting infected in these instances is, however, quite remote.

(iii)Mother to infant: Women who are infected by the virus may pass the infection to their infant during pregnancy, around the time of birth, or during breast feeding.

HIV is not spread through air or social contact. It cannot be contracted by shaking hand, travelling, eating together, attending school, working or sharing toilet with a person infected with HIV. There is also no evidence to suggest that HIV is spread by mosquito and other insect bites.

About half of those who are HIV infected will develop AIDS within ten years. The others may be free of any signs and symptoms. They cannot be identified by appearance but can pass the virus to other persons. Currently HIV cannot be eradicated. There are effective drug treatments to suppress the virus, restore the body immune system, delay the development of AIDS, prevent and treat opportunistic infections and hence death, and improve the quality of life of those infected people. Therefore, those people living with HIV are advised to be positive in facing their HIV positive status.

HIV infection and AIDS do not present with specific symptoms or signs. If you are worried about being infected because of suspected exposure, you should seek counselling and consider undergoing the HIV antibody test.

You should not go for blood donation if you are at risk of HIV infection, because during the first 3 months after infection, the body may not have produced enough antibodies to show up in the test. If your blood is carrying the HIV, and you go for blood donation then, you may unknowingly spread the virus to others even though you are tested negative.

If you have any queries, you are advised to talk to the AIDS counsellor, at 2780 2211 or you may consult your doctor.


3. Sexually transmitted infections and pregnancy

Sexually transmitted infection is serious in that it will affect the sex organ, cause sterility or even affect the patient's offspring, but generally speaking, in case of early detection and proper treatment offered, sexually transmitted infection will not affect the patient's capability of sexual reproduction nor his /her offsprings.

The following are the effects of sexually transmitted infections on pregnancy:

Syphilis transmitted from mother to baby. The present antenatal checkups offered by the Department of Health or Hospital Authority include a blood test for syphilis. Early detection of the latent infection and proper treatment can prevent the spread of syphilis to the offspring and thus obviate the need for artificial abortion.

Some sexually transmitted infections can be accurately diagnosed only with special examination. Examples include gonorrhoea, non-specific genital infections, herpes and genital warts. During pregnancy, if infection of the aforesaid diseases are suspected or you have had sexual intercourse with a partner suspected to be infected with such diseases, you should notify the obstetrician or doctors of the social hygiene clinic so that further examination and early treatment can be offered. This can prevent both the pregnant woman and her foetus from being infected.

HIV can be transmitted to the offspring from an infected pregnant woman. Anyone who suspects herself to be infected with HIV should seek the doctor's counselling and receive an HIV antibody test before embarking on pregnancy. Currently, HIV antibody routine screening is adopted in the public antenatal services under the Department of Health and Hospital Authority (the attending pregnant women may however opt not to be tested according to their own will). If any of the expectant mothers are found to be HIV-positive, they will be counselled by the concerned doctors with the support of the nurse counsellor and social worker on issues such as the available treatment options (including those intended for prevention of mother to child transmission of HIV), the potential adverse effects of such treatments, the risk of vertical transmission to the baby, the natural course of HIV infection, the possible psycho-social effect of HIV infection to the woman, the expectant baby and her family. Scientific evidence shows that the chance of mother to child transmission of HIV can significantly be reduced with the use of early and appropriate drug therapy and adoption of appropriate mode of delivery. The transmission rate is less than 5% nowadays in countries, including Hong Kong, with modern antenatal health care infrastructure. The decision of the pregnant woman (and her family) will be highly respected. The concerned staff will render support to those women (and families for those women who opt to disclose such information to their families) for them to live with HIV infection.

Pregnant woman should in no way try to cure the suspected venereal disease by self-medication because the medicine she uses may do harm to the foetus. In case of queries, the obstetrician should be consulted as soon as possible.

It is of utmost importance to prevent sexually transmitted infections and AIDS during pregnancy. If you cannot confirm whether your sex partner is free from infection, condoms should be used properly.



Social Hygiene Service Clinics Information

Clinics provide Social Hygiene Service (Female)
Clinics provide Social Hygiene Service (Male)