For the diagnosis of infections by bacteria, fungi, viruses and parasites, laboratory tests are often required.
If a bacterial or viral infection is suspected, a so-called skin swab is usually taken with a cotton swab. A culture or PCR is carried out in the laboratory. The result is usually already available after 1-2 days. Bacteria or viruses that are detected in the blood by the immune system can also be diagnosed with an examination of the blood (serology). Urine tests are carried out if there is suspicion of a bacterial infection of the urinary tract.
If a fungal infection is possible, skin scales, nail material or hair are examined. In the direct preparation, which is carried out in the practice, a fungal infection can often be diagnosed or excluded. A culture lasting 4-6 weeks is necessary to determine which fungus is involved.
Depending on the pathogen, infections caused by parasites can be examined in a direct preparation, by stool culture or in the blood.
In the case of symptoms such as itching, hair loss, brittle nails or corner of the mouth rhagades, which persist for a longer period of time, the exclusion of a deficiency of vitamins and trace elements (such as iron or zinc) is important.
Diseases of organ systems
Many diseases of the organ systems such as liver, kidney, thyroid or blood diseases present themselves with symptoms on skin, hair and nails. Blood tests may be necessary because the diagnosis cannot usually be made on the basis of appearance alone.