Skin cultures are a rarely ordered test unless there is an especially nasty skin infection that is endangering the organ. Normally, skin infections can be dealt with by the body itself but in the case of very young children and in the case of immune-compromised patients, the normally latent bacteria and fungi on the skin can turn rogue and cause severe infections like cellulitis. A skin culture test is sometimes used to refer to the Mantoux test that is used to diagnose tuberculosis but this is a completely different type of test compared to the skin tests that use skin culture peels. Usually, the exudates from infected sores are all that are required for skin culture tests though in the case of cellulitis, a skin culture peel might be required.
A skin culture test is performed to figure out the specific type of pathogenic infection in the skin. Generally, a good and trained medical eye can identify the causative organism by just looking at the type of wound that the organism has caused. Fungi for example, don’t target the living areas of the skin and instead will attack the topmost epidermal layer of the skin as they usually feed on skin keratin and sebum. Bacteria can and will go deeper if given a chance. Viruses can also infect the skin in diseases like the cold sores but this is usually just an outward manifestation of a more serious infection within the body. The herpes virus, in fact, requires the creation of sores to propagate beyond the immediate host.
A skin culture test is generally performed by taking some of the exudates from the sores or a sample of the pus. In immune compromised individuals, this option may not be available. This is especially the case in diabetics with cellulitis. In this case, a swathe of infected skin may need to be taken for sampling. The sample is then grown in a lab or directly stained and checked under a microscope to identify the pathogen.
There is no preparation to be done for this test as all the tests will use material that is under the skin or will take an entire skin sample. Note that this test could be painful and therefore, you must be prepared for a needle aspiration or for a skin sample to be taken from you.