This is an aggregation of fluid that appears as an enlargement in the scrotal region of the male infant.
Hydrocoeles are usually small, but they may be large and present problems. They can sometimes be confused with an inguinal hernia, for their location, size and appearance is quite similar.
A way of telling the difference between them is that a hydrocoele will sometimes “transilluminate.” This means that if a small pencil torch is held close into it, it will light up like a globe, as the light beam “transilluminates” through the fluid contents. A hernia has more solid contents (bowel, often) and will not react in this manner.
It is wise to have such a swelling examined by the doctor as soon as it becomes evident. Small ones tend to disappear with time, but a large hydrocoele, especially if it is producing discomfort or irritation to the child, may be better removed surgically.
The doctor will give the appropriate advice after examining it, perhaps on a few successive occasions.