Psoriasis By Shinjita Das, MD, Harvard Medical School Reviewed / Revised Aug 2021 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Treatment Key Points More Information Topic Resources Psoriasis Plaque Psoriasis (Plaques) Psoriasis (Elbows) Psoriasis (Fingers) Psoriasis (Scalp) Nail Psoriasis With Pitting... Nail Psoriasis With Thickening... Pustular Psoriasis (Feet) Acrodermatitis Continua of... Inverse Psoriasis Guttate Psoriasis Erythrodermic Psoriasis Palmoplantar Psoriasis (Palm) Palmoplantar Psoriasis (Sole) Palmoplantar Pustulosis Subtypes of Psoriasis Psoriasis is an inflammatory disease that manifests most commonly as well-circumscribed, erythematous papules and plaques covered with silvery scales.