Satellite lesions, also called secondary lesions, can be caused by many different things. They are called satellite or secondary because they are found close to main lesions. These lesions are responses to conditions that have not received treatment quickly or adequately. The main causes of the lesions are the primary lesions, but the underlying causes of the primary lesions are also the cause of the secondary lesions. Candidiasis, staphylococcus aureus bacteria, and cancer are the most common conditions that cause lesions.
Candidiasis is a fungal infection and is also known as a yeast infection, diaper rash, or thrush. This infection is most commonly diagnosed when lesions appear on the skin, but can also occur in the intestines, mouth, or bladder. Red welts with inflammation appear on the skin, while inner lesions are white or gray in color. Satellite lesions occur if the infection worsens or does not respond to initial treatment.
The staphylococcus aureus bacteria can lead to many skin problems. Primary lesions are sores on the skin that will often be fluid-filled and have a light gray or yellow crust cover. In this instance, satellite lesions appear in clusters closer to the primary lesions, which can make them look worse and larger than what they really are. Prompt antibiotic treatment can prevent secondary lesions from appearing.
Some cancers, such as melanoma, are often diagnosed by the presence of lesions. Not all forms of cancer cause lesions or have lesions that are on the skin, but many cause lesions inside the body. During diagnosis, doctors look for satellite lesions to help them differentiate or confirm an initial diagnosis from a primary lesion. With melanoma, for example, secondary lesions will be smaller than the primary lesions but otherwise very similar in color and shape.
Diagnosing the underlying cause is an important factor in preventing satellite lesions. Primary lesions play a large role in determining what the cause is. Once a diagnosis is made, proper treatment can help reduce the chance that secondary lesions will occur. Doctors may also use the presence of secondary lesions to monitor the effectiveness of treatment for conditions that caused primary lesions, particularly if no secondary lesions were present when treatment began.
In some cases, doctors may need to biopsy a primary and/or secondary lesion. This process involves testing a tissue sample of the lesion to determine what the cause is. If the lesions are on the surface of the skin, a simple cut is made. Internal lesions, however, may require endoscopy or a surgical procedure to get biopsy samples.