Differential Diagnosis for a Painful Small Nodule on the Lower Right Eyelid
- Single Most Likely Diagnosis
- Hordeolum (Stye): A common, localized infection or inflammation of the eyelid margin involving hair follicles of the eyelashes (external hordeolum) or meibomian glands (internal hordeolum). The presentation of a painful nodule with thick yellow pus discharge is highly suggestive of a hordeolum, especially given the acute onset and localized nature of the symptoms.
- Other Likely Diagnoses
- Chalazion: An inflammatory lesion of the eyelid caused by a blocked meibomian gland. While it tends to be less painful and has a more gradual onset than a hordeolum, it can become secondarily infected, leading to increased pain and discharge.
- Blepharitis: Inflammation of the eyelids that can cause redness, itching, and swelling. It may lead to the formation of a nodule or increase the risk of developing a hordeolum or chalazion.
- Eyelid Abscess: A localized collection of pus in the eyelid, which can result from an infection of the skin, a hordeolum, or a chalazion. It presents with significant pain, swelling, and possibly discharge.
- Do Not Miss Diagnoses
- Orbital Cellulitis: An infection of the soft tissues surrounding the eye, which can lead to serious complications, including vision loss, if not promptly treated. While the patient reports no systemic symptoms or vision changes, the potential for rapid progression and severe outcomes makes this a critical diagnosis not to miss.
- Dacryocystitis: An infection of the lacrimal sac, usually presenting with pain, swelling, and discharge in the medial canthus area. It's less likely given the location of the nodule but could be considered if there's involvement of the lacrimal apparatus.
- Rare Diagnoses
- Malignant Tumors (e.g., Basal Cell Carcinoma, Squamous Cell Carcinoma): Although rare, these can present as nodules on the eyelid. The acute onset and presence of pus make this less likely, but it should be considered in the differential, especially if the lesion does not respond to typical treatments for more common conditions.
- Xanthelasma: A condition characterized by the accumulation of lipid-laden macrophages in the skin, leading to yellowish patches or nodules on the eyelids. It's usually asymptomatic and not associated with acute pain or discharge, making it an unlikely diagnosis in this scenario.