Rubella, also known as the German measles, can be diagnosed clinically based on signs and symptoms of the disease. A rubella diagnosis can also be made based on serologic findings using a blood test done on the person infected. Whether or not the blood test is needed for a rubella diagnosis, is dependent on the skill of the physician and on the clinical situation.
A rubella diagnosis should be considered in anyone who presents with a fever, headache, swollen lymph glands and a red rash on the face that spreads to the trunk and then the limbs and goes away in three or four days. The rash consists of hundreds of small, red bumps or papules that feel like sandpaper. The fever and swollen lymph nodes persist longer than the rash. Joint pain is common in adults.
Another way to make the rubella diagnosis is through blood tests. Immunoglobulins (IgM and IgG) rise in response to an exposer. The IgM goes up in the acute phase when there is an active infection. The IgG rises and gives immunity to the disease after an active infection or in response to a vaccine. If it is suspected, a patient has rubella then the titer of these can be measured. A high IgM indicates active infection and especially if the IgG is low the rubella diagnosis can be made.
Rubella is typically a mild illness for both children and adults. Problems from rubella arise when the virus is contracted by a pregnant woman especially in the first trimester. Congenial rubella syndrome can cause cardiovascular, auditory, opthalmologic, and cerebral defects. A Congenial rubella diagnosis can be suspected when the mother has blood titer that is low in rubella IgG and her rubella IgM rises. These blood tests can be measured after a rubella exposer.