Private lump in the neck clinic in London, same-day GP.

The common harmless causes

• Reactive lymph nodes — small, tender, mobile, appearing with a sore throat, cold, dental infection or skin infection. They shrink over two to four weeks. The commonest cause by far.
• Sebaceous or epidermoid cysts — in the skin, sometimes with a central punctum.
• Lipoma — soft, doughy, mobile, slow-growing.
• Thyroid nodules and goitre — in the midline, moving up when you swallow.
• Salivary gland swelling — in front of or below the ear, sometimes worse before meals if a stone is blocking the duct.
• Branchial cysts and thyroglossal cysts — congenital, usually presenting in younger people.

What investigation involves

• Examination of the neck, mouth, throat, thyroid, skin and scalp — the source is often found somewhere obvious.
• Blood tests — full blood count, inflammatory markers, LDH, thyroid function, and tests for glandular fever, HIV or TB where relevant.
• Ultrasound — the first-line imaging test, distinguishing cystic from solid and assessing the characteristics of nodes and thyroid nodules.
• Fine needle aspiration under ultrasound where a sample is needed.
• Flexible nasendoscopy to examine the throat and voice box, particularly with hoarseness or swallowing difficulty.
• CT or MRI where further mapping is required.

In children

Small, mobile neck nodes are extremely common in children and usually reflect frequent viral infections — many healthy children have palpable nodes most of the time. Assessment is warranted for a node larger than 2cm, one that is growing, hard or fixed, one above the collarbone, or any node with fever, weight loss, night sweats or unusual bruising.

What not to do