RT Book, Section A1 Goldfarb, Noah A1 Schultz, Brittney A2 Soutor, Carol A2 Hordinsky, Maria K. SR Print(0) ID 1190940280 T1 Skin Diseases of the Arms T2 Clinical Dermatology: Diagnosis and Management of Common Disorders, 2e YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264257379 LK accessmedicine.mhmedical.com/content.aspx?aid=1190940280 RD 2024/04/24 AB Many skin conditions that affect the arms result from their direct exposure to sunlight, contact with allergens or irritants, trauma, bug bites, and other environmental insults. The arms are within close reach of the contralateral hand, so patients can easily scratch pruritic dermatoses. Scratching or trauma may produce a linear streak of papules (Koebner phenomenon) in certain diseases such as psoriasis and lichen planus. Some skin diseases have a predilection for specific locations on the arms. While it is unknown why many dermatoses tend to localize to certain anatomical locations, lesion distribution is frequently a very important clue to establish diagnosis.