Differential Diagnosis for Itching after Pressure Applied

• Single most likely diagnosis
  • Dermographism: This condition is characterized by an itchy, raised rash that appears after pressure is applied to the skin, making it a likely cause for itching after pressure.
• Other Likely diagnoses
  • Urticaria: This condition involves itchy hives that can be triggered by pressure, among other factors, making it a plausible diagnosis.
  • Pressure urticaria: A subtype of urticaria that is specifically caused by pressure, leading to itchy lesions.
  • Contact dermatitis: While typically associated with allergens or irritants, certain types of contact dermatitis could potentially be exacerbated by pressure, leading to itching.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Angioedema: A severe, potentially life-threatening condition that can cause swelling and itching, often in response to allergens or other triggers, including pressure in some cases.
  • Erythromelalgia: A disorder that causes burning pain, heat, and itching, usually in the hands and feet, which could potentially be exacerbated by pressure.
• Rare diagnoses
  • Mastocytosis: A rare condition characterized by an accumulation of mast cells in the skin, which can lead to itching, hives, and other symptoms, potentially triggered by pressure.
  • Sickle cell disease: In rare cases, sickle cell disease can cause itching due to various mechanisms, including possible reactions to pressure, though this is less common.
  • Polycythemia vera: A rare blood disorder that can cause itching, often after hot showers but potentially after other stimuli, including pressure, due to histamine release.