Differential Diagnosis for a Sore on the Right Side of the Neck
- Single most likely diagnosis:
- Infected sebaceous cyst: The patient's history of a long-standing bump that recently became painful, red, and swollen after a traumatic event (feeling a "crunch" while washing his face) suggests an infected sebaceous cyst. The pain radiating to the jaw could be due to inflammation or infection spreading to adjacent tissues.
- Other Likely diagnoses:
- Abscess: Similar to an infected sebaceous cyst, an abscess could present with pain, redness, and swelling, especially if it has recently ruptured or become infected.
- Furuncle or carbuncle: These are infections of the hair follicle that can cause pain, redness, and swelling, and could be considered given the acute onset of symptoms after a minor trauma.
- Lymphadenitis: Inflammation of the lymph nodes in the neck could cause pain, swelling, and redness, especially if there is an underlying infection.
- Do Not Miss diagnoses:
- Parotid gland infection or abscess: Given the pain radiating to the jaw, an infection or abscess of the parotid gland should be considered, as it can be a serious condition requiring prompt treatment.
- Necrotizing fasciitis: Although rare, this is a life-threatening condition that can present with pain, swelling, and redness, and should be considered in the differential diagnosis, especially if the patient's symptoms worsen rapidly.
- Malignancy: Although less likely, a malignant process such as a metastatic lymph node or a primary tumor of the skin or salivary gland should be considered, especially if the patient has a history of cancer or if the lesion does not respond to treatment.
- Rare diagnoses:
- Branchial cleft cyst infection: A congenital anomaly that can become infected and present with pain, swelling, and redness in the neck.
- Thyroglossal duct cyst infection: A congenital anomaly that can become infected and present with pain, swelling, and redness in the neck.
- Actinomycosis: A rare bacterial infection that can cause chronic abscesses or masses in the neck, which could be considered if the patient's symptoms do not respond to typical treatments.