Down syndrome (DS), or trisomy 21, is the most common chromosomal condition diagnosed in the United States with an estimated worldwide incidence of one in every 1000 births. About 200-300 genes are found on chromosome 21, and the added gene products translate to a variety of potential medical conditions. Although often overlooked in research and health care guidelines, the skin can be significantly affected in people with DS. 1,2 A study on the prevalence of medical conditions in young adults with DS found 56% of those surveyed reported skin findings. 3 In this review, a general overview of DS and practical examination strategies are provided. We comprehensively review associated dermatologic conditions, with particular emphasis on more common diseases including adnexal, eczematous, and cutaneous autoimmune disorders (Table 1). Throughout the review, trisomy of chromosome 21 and resulting downstream effects are explored, in particular the effect on the immune system. At the conclusion, clinicians should feel confident in their approach to a patient with DS and anticipate potential dermatologic diagnoses.
| OVERVIE W OF DOWN SYNDROMEAn estimated 200,000 individuals with DS reside in the United States today. 4 Certain medical conditions are more common, including hearing deficits, visual problems, hematologic/oncologic disorders, congenital heart disease, and endocrinopathies. 5 Elevated body mass index (BMI) is also highly prevalent and a recent literature review found up to 70% of people with DS were classifed as overweight or obese. 6 This could be relevant to several skin conditions including hidradenitis suppurativa and psoriasis.Features of both immunodeficiency and immune dysregulation are common in DS. Upper and lower respiratory tract infections result in significant morbidity and mortality. 7 Autoimmune conditions such as Hashimoto thyroiditis, celiac disease, type I diabetes, alopecia areata, and juvenile idiopathic arthritis are more frequent. 5 The extent of immune dysregulation is complex. Current research suggests dysfunction of innate and adaptive systems, anomalies in T and B cells, atypical monocytes, impaired neutrophil chemotaxis, abnormal circulating cytokines, and suboptimal antibody responses. 8 The skin offers a unique window into understanding these immune pathways.While many known complications in DS are found, medical benefits are also well described. These include a reduced incidence of solid organ tumors, atherosclerotic disease, hypertension, thromboembolic stroke, asthma, and allergy. 9-14 These observations will be of particular interest when we discuss hidradenitis suppurativa (HS), psoriasis, eczematous dermatitis, and cutaneous malignancies in patients with DS.