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Dermatology Morphology Basics: Building Differentials & Primary vs Secondary Lesions | The Derm Resident

Hosts Dr. Jonny Hatch and Dr. Deven Curtis introduce The Derm Resident and outline the podcast’s goal of reviewing dermatologic diseases by pathogenesis, clinical features, workup, and management to help with clinic and boards. They discuss an approach to building differentials using a “tree” framework (neoplastic vs inflammatory, then infectious vs noninfectious) and emphasize that morphology is the core language of dermatology, sometimes outweighing patient history. The episode reviews key primary lesions—macule vs patch, papule vs plaque, nodules, wheals, vesicles vs bullae, and pustules—and explains why precise word choice matters. They then cover secondary changes including scale vs crust, fissures, excoriations, erosions vs ulcerations, atrophy, and lichenification, and end by stressing the importance of palpation in lesion assessment.

00:00 Welcome to the Podcast
00:52 How to Build a Differential
02:38 Disease Buckets and Pathogenesis
05:56 Morphology Is King
08:43 Primary Lesions Basics
11:54 Nodules and Wheals
14:49 Blisters and Pustules
19:52 Secondary Lesions Explained
21:06 Scale vs Crust and Micaceous
24:10 Breaks in the Skin
27:46 Atrophy and Lichenification
30:10 Palpation Pearls
32:17 Wrap Up and Next Episode