Medical Knowledge

Test-Negative Study Designs for Evaluating Vaccine Effectiveness

This JAMA Guide to Statistics and Methods article explains the test-negative study design, an observational study design routinely used to estimate vaccine effectiveness, and examines its use in a study that estimated the performance of messenger RNA boosters against the…

Rapidly Growing Eyelid Lesion in a 73-Year-Old Man

A man aged 73 years presented with a 5-day history of a fast-growing right eyebrow nodule with raised borders and central ulceration. There was no discomfort, and the patient denied vision changes. The lesion was refractory to treatment with erythromycin,…

Solid Facial Edema

This case report describes nonpitting erythematous edema on the forehead, glabella, nose, and cheeks.

Bilateral Retinal Vascular Tortuosity and Hemorrhages

A 28-year-old man presented with decreased visual acuity in his right eye for the past 2 weeks. Examination revealed dilated and tortuous veins, Roth spots, and white intraretinal agglomerates. What would you do next?

A Man in His 50s With Dyspnea and Eosinophilia

A man in his 50s presented with progressive dyspnea, eosinophilia (eosinophils, 3.27 × 109/L; to convert to /μL, divide by 0.001), thrombocytopenia (platelet count, 53 × 109/L; to convert to × 103/μL, divide by 1), and elevated troponin T level…

Lymphoma With a Skin Rash

A 62-year-old female had a generalized vesiculobullous rash on her face for 4 months. It started over the lips and gradually progressed to involve the oral mucosa and skin of the whole body. What is your diagnosis?