Syphilis is contracted through sexual intercourse with an infected person. Micro-injuries to the skin and damaged mucous membranes become sites of entry for the micro-organism.

Approximately 5-21 days after penetration, a lesion forms, known as a primary ulcer, which is not painful and is accompanied by involvement and enlargement of the lymph nodes. The most common location of entry of the pale spirochete is in the genitals and around the mouth. This stage of the disease is called 'primary syphilis'. After about three to six weeks, the next stage, called 'secondary syphilis', begins. This is when the micro-organism spreads through the bloodstream and causes a papular-spotted rash. Occasionally, a latent period can occur, which is completely asymptomatic and affects patients whose immune system is very efficient. If dormant spirochetes are reactivated after the latent period, tertiary syphilis symptoms appear, involving the heart and central nervous system.

If a pregnant woman has syphilis, the infection can be transmitted to the foetus, especially if the woman is untreated. Transmission of the spirochete through the placenta is possible at any time during pregnancy, but most commonly after the 16th to 18th week of pregnancy. A child who is infected in foetal life will develop what is known as 'congenital syphilis'.

Depending on the severity of syphilis, the symptoms can be varied. In addition to those mentioned earlier, very characteristic and frequent symptoms include: a non-itchy papulopustular rash on the palms and soles, oozing, eruptive warts containing numerous spirochetes occurring in the anal and genital areas - condyloma planus, mucosal eruptions, syphilitic alopecia and syphilitic vitiligo (mainly on the neck - the so-called 'Venus necklace'). The clinical picture of congenital syphilis, on the other hand, depends on the time of infection: the earlier, the more severe the course. Early sy philis manifests itself in the neonatal period, usually between 6-10 weeks of age, so that immediately after birth, the course is usually completely asymptomatic. When symptoms do appear, they take the form of what is known as 'Hutchinson's triad' and include: keratitis, deafness and Hutchinson's teeth (barrel-shaped with a crescent-shaped hollow in the centre).

Appropriate antibody tests and a haemagglutination test should be performed to make the diagnosis. As a matter of urgency, a swab can also be taken from the lesion and the spirochetes visualised directly under the microscope.

If clinical and ambulatory data confirm infection, an appropriate treatment regimen should be implemented. This consists of intramuscular administration of benzylpenicillin for 14 days if the disease lasts less than 1 year or for 21 days if the disease lasts more than 1 year.