An 8-month-old male British Blue cat has a lump under the skin that hurts when pressed, but no other symptoms; energetic with normal appetite

A subcutaneous lump in a cat can have several causes. If it is at the neck after recent vaccination or injection, it may be poor drug absorption or rejection; if it is not growing, daily warm compresses and massage can help absorption.

Tumor growth is another possibility, especially if the cat shows strong pain when the lump is touched lightly; a cytology exam at the clinic is advised, and surgical removal is needed for subcutaneous tumors.

Skin infection or parasite bites can also cause lumps. Check the skin through the fur; if parasites are found, apply a topical flea and tick treatment. For skin-disease lumps, confirm the type first and treat accordingly.