Differential Diagnosis for Itchy Skin with Bruising upon Scratching

• Single most likely diagnosis
  • Dry Skin (Xerosis): This condition is very common and can cause intense itching. Scratching can lead to bruising, especially in older adults or those with fragile skin.
• Other Likely diagnoses
  • Eczema (Atopic Dermatitis): Characterized by itchy, inflamed skin that can become bruised with scratching.
  • Psoriasis: An autoimmune condition that speeds up the life cycle of skin cells, leading to itchy, scaly patches that may bruise if scratched vigorously.
  • Urticaria (Hives): Can cause itchy skin, and if the hives are scratched, they may bruise.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Mastocytosis: A condition where mast cells accumulate in the skin, leading to severe itching and potentially life-threatening allergic reactions if not properly managed.
  • Leukemia Cutis: Skin involvement in leukemia, which can present with itchy skin lesions that may bruise easily due to thrombocytopenia or platelet dysfunction.
  • Amyloidosis: A group of diseases that can cause itchy skin, and the scratching may lead to bruising due to the potential for coagulopathy.
• Rare diagnoses
  • Sjögren's Syndrome: An autoimmune disorder that can cause dry, itchy skin, among other symptoms, and scratching may lead to bruising.
  • Sickle Cell Disease: Certain skin manifestations can be itchy, and due to the disease's effect on blood cells, bruising may occur more easily.
  • Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues, potentially leading to fragile skin that bruises easily when scratched due to itching.