The prominence of bone directly behind the ear is part of the skull called the mastoid process. This area is a common site of discomfort, and soreness here can range in origin from a minor infection to a systemic issue. The mastoid bone is a portion of the temporal bone. Soreness can be confusing because the cause is not always the bone itself, but often a nearby structure or an issue originating further away.
Swollen Glands and Localized Irritation
A frequent, non-threatening cause of tenderness behind the ear involves the lymphatic system. Lymph nodes, specifically the posterior auricular nodes, are situated directly over the mastoid bone and swell when they activate to filter pathogens. This swelling, known as lymphadenopathy, is a normal response to infections in the surrounding areas, such as the scalp, throat, or ear. Common colds, strep throat, or a simple ear infection can lead to these nodes becoming enlarged and tender to the touch.
Pain can also arise from localized skin issues independent of the bone or deep infection. Conditions like folliculitis (inflammation of the hair follicles) or a sebaceous cyst can develop on the skin overlying the mastoid process. These minor irritations create localized swelling and soreness. Once the underlying infection or irritation resolves, the lymph nodes typically return to their normal size.
When Pain Signals a Serious Infection
One specific cause of pain centered on this bone is mastoiditis, a bacterial infection of the mastoid process itself. The mastoid bone is not solid; it has a delicate, honeycomb-like structure filled with air cells that connect to the middle ear. This anatomical connection means that a severe or inadequately treated middle ear infection (otitis media) can spread into the porous bone structure.
When the infection takes hold within the mastoid air cells, the resulting inflammation causes the bone to begin breaking down, leading to pus accumulation. Symptoms of mastoiditis progress beyond simple earache and include intense, throbbing pain behind the ear. The infection causes noticeable swelling and redness in the area, sometimes pushing the earlobe visibly outward or forward.
Additional signs of this deeper infection include a high temperature, lethargy, and a copious discharge from the ear. Because the infection is located within the bone, treating mastoiditis often requires strong intravenous antibiotics. Without prompt and effective treatment, the infection can spread to other areas, potentially leading to complications such as facial paralysis or brain abscesses.
Referred Pain from the Jaw or Neck
Sometimes, the sensation of soreness in the mastoid bone does not originate from a local issue but is a phenomenon known as referred pain. This occurs when pain signals are generated in one area but are perceived by the brain as coming from a different, nearby location due to shared nerve pathways. The temporomandibular joint (TMJ) is a common source of this discomfort because it sits immediately in front of the ear.
Dysfunction in the TMJ, often caused by jaw clenching, teeth grinding, or misalignment, can inflame the surrounding muscles and nerves. This tension irritates nerve branches that also supply sensation to the ear and the area behind it, causing pain to radiate toward the mastoid process. This type of referred pain is frequently accompanied by symptoms like clicking or popping of the jaw, difficulty chewing, or tension headaches.
Muscles in the neck can also contribute to this referred sensation. Chronic muscle strain or tension in the upper neck can generate trigger points that radiate discomfort upward. Therefore, a deep ache felt behind the ear might be a signal of muscular tension or spinal misalignment rather than an infection in the bone itself.
Recognizing Red Flags and Seeking Care
While many causes of pain behind the ear are minor, certain symptoms indicate a medical concern that requires immediate professional evaluation. A high or persistent fever, especially when combined with a worsening earache, should prompt a visit to a healthcare provider. Any visible bulging or displacement of the ear, where it appears to stick out further than the other ear, is a serious sign of mastoiditis and requires urgent attention.
Other concerning red flags include severe pain that does not improve with over-the-counter pain relievers or any new sign of systemic illness, such as confusion or severe lethargy. Persistent drainage from the ear that contains pus, or any new weakness or asymmetry in facial muscles, are also indicators of a spreading infection. It is prudent to consult a doctor if the pain behind the ear is accompanied by these signs or if the soreness continues for more than a few days without improvement.