Candida esophagitis: This is the most common cause of nummular lesions in the esophagus, particularly in immunocompromised patients. The lesions are typically white, round, and well-defined, and are often associated with oral thrush.

Herpes simplex virus (HSV) esophagitis: HSV can cause nummular lesions in the esophagus, often accompanied by symptoms such as odynophagia and dysphagia. The lesions are typically small, discrete, and may be surrounded by a halo of erythema.
Cytomegalovirus (CMV) esophagitis: CMV can cause nummular lesions in the esophagus, particularly in immunocompromised patients. The lesions are often larger and more ulcerative than those caused by HSV.
Esophageal ulcers: Esophageal ulcers can present as nummular lesions, often caused by gastroesophageal reflux disease (GERD), medications, or other factors.

Esophageal cancer: Although less common, esophageal cancer can present as nummular lesions, and it is crucial to rule out this diagnosis to avoid delayed treatment.
Infectious esophagitis due to other pathogens: Other infectious agents, such as bacteria or viruses, can cause nummular lesions in the esophagus, and it is essential to consider these possibilities to provide appropriate treatment.

Esophageal lymphoma: Esophageal lymphoma is a rare condition that can present as nummular lesions, often accompanied by systemic symptoms such as weight loss and fatigue.
Esophageal granulomatosis with polyangiitis (GPA): GPA is a rare autoimmune disorder that can cause nummular lesions in the esophagus, often accompanied by other systemic symptoms such as respiratory and renal involvement.
Esophageal histoplasmosis: Histoplasmosis is a rare fungal infection that can cause nummular lesions in the esophagus, particularly in immunocompromised patients.