Black crusts on the palate are commonly associated with pulmonary trichinosis. Pulmonary trichomycosis is a pulmonary infectious disease caused by pathogenic bacteria of the order Trichophyton. Although rare, it develops rapidly and has a high mortality rate, with Trichoderma and Rhizopus being more common in clinical practice. So how is the differential diagnosis of black scorch on the palate made? The following is an introduction. Differential diagnosis of black scab on the palate Black scab on the palate is often differentiated from oral ulcers. The former mainly invades the lungs, while the latter mostly involves the sinuses, eyes, brain and gastrointestinal tract, and can be hematologically disseminated to the whole body. Pulmonary trichinosis can be a primary infection, but also secondary to sinus lesions or trichinosis sepsis. The disease begins as a symptom of acute bronchitis, and when the lungs are involved, it causes solid lung changes and lung abscesses, with signs of thrombosis and infarction. Oral ulcers, also known as “mouth sores”, are superficial ulcers on the oral mucosa, ranging in size from rice grains to soy beans, round or ovoid in shape, with the ulcerated surface being a concave mouth ulcer, surrounded by congestion, which can be painful due to irritating foods, and can generally heal spontaneously in one to two weeks. Mouth ulcers become recurrent periodically, medically known as “recurrent mouth ulcers”. It can occur several times a year, or several times a month, or even alternating old and new lesions.