Hone your clinical reasoning and diagnostic skills with a new series of case-based topic-specific studies. This compilation of twenty dermatology cases from Pediatrics in Review can help increase your knowledge of skin diseases in children, encourage you to appreciate how morphology of skin disease can provide a wealth of diagnostic clues, and challenge you to think about the diverse dermatologic presentations. Cases include patients with uncommon variants of common pediatric skin conditions, as well as findings that on initial presentation can be alarming, like certain genital lesions or acute pigmented lesions. Several cases present with congenital or acquired “lumps and bumps that are moderately common, and learning more about these conditions may enable you to recognize and distinguish them from mimickers and be aware of when they may be a sign of associated systemic features. There are several reports of patients with rare rashes that can have a significant risk for systemic morbidity. Being alert to the ways in which these conditions present will prepare the practitioner to consider these entities when assessing patients with similar presentations.