4. Mucous Patches
The mouth and the genitals both contain different types of glands than any other part of the body. Mucous patches may appear on the surface of the genitals or the surface of the mouth when a person has been infected with syphilis. It is possible for mucous patches to appear on other parts of the body as well, especially those areas that are subject to moisture and heat. When secondary syphilis sets in it can cause different changes in the tissue to occur.
These changed processes may cause irregularities in the production of mucus. The surface of the skin may become blocked or clogged with this mucus. When the mucus cannot get through the outer layer of the skin it can cause the area to become irritated and swollen. This is one of the symptoms of syphilis that will not go away until it is properly treated.