Cancer, certain viral or bacterial infections and autoimmune diseases may cause a lump on the back of the neck, notes Healthline. A neck lump may also occur due to an injury or torticollis. These factors result in the enlargement of lymph nodes, a common cause of the neck mass.
Human papilloma virus infection and prolonged use of tobacco or alcohol cause cancers of the neck in adults, states Healthline. Cancerous neck lumps are likely to occur in individuals who are above 40 years. These cancers include leukemia, cancers of the head and neck, Hodgkin’s disease and non-Hodgkin’s lymphoma.
Viral infections that can cause lumps on the back of the neck include HIV/AIDS, rubella, herpes, infectious mononucleosis and viral pharyngitis, according to Healthline. Peritonsillar abscess, tonsillitis, tuberculosis and atypical mycobacterium are bacterial conditions that may bring about neck lumps. Other such conditions include strep throat and cat scratch disease. These lumps are normally treated with antibiotics.
Stones in the salivary duct, and allergic reactions to certain foods or medications may lead to neck lumps, notes Healthline. Disorders of the thyroid gland, such as goiter that occurs as a result of iodine deficiency, may cause thyroid glands to enlarge, resulting in a lump on the neck. Symptoms associated with neck lumps include difficulty swallowing, hoarseness, bloody saliva or phlegm, and weight loss due to hyperthyroidism or HIV/AIDS.