Eczema, nummular: Coin-shaped plaques of inflamed skin-most common on the arms, back, buttocks, and lower legs that may be crusted, scaling, and extremely itchy. The word "nummular" is taken from the Latin "hummus," a small coin. SLIDESHOW Rosacea, Acne, Shingles, Covid-19 Rashes: Common Adult Skin Diseases See Slideshow From Skin Problems and Treatments Resources Tips for Dry SkinSensitive Skin? How to keep skin healthy.Stop the Scratching Featured Centers Good and Bad Foods for PsoriasisVideo: Getting Personal on Life With MS Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19