Differential Diagnosis for Pruritic Scaly Plaques that Bleed with Removal

• Single most likely diagnosis:
  • Psoriasis: This condition is characterized by well-demarcated, erythematous, scaly plaques that can bleed upon removal of the scales (Auspitz's sign), making it a prime candidate for the described symptoms.
• Other Likely diagnoses:
  • Eczema (Atopic Dermatitis): Presents with pruritic, scaly lesions that can become excoriated and bleed due to scratching.
  • Seborrheic Dermatitis: Causes scaly, itchy plaques on the scalp, face, and other areas, which can bleed if scratched or removed.
  • Contact Dermatitis: An allergic or irritant reaction causing itchy, scaly lesions that may bleed upon removal of the offending agent or due to scratching.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Malignant Lesions (e.g., Squamous Cell Carcinoma): Although less common, these can present as scaly, bleeding lesions, especially in sun-exposed areas or in immunocompromised patients.
  • Invasive Fungal Infections: In severely immunocompromised patients, fungal infections can cause lesions that are pruritic, scaly, and may bleed, requiring prompt and aggressive treatment.
• Rare diagnoses:
  • Pityriasis Rubra Pilaris: A rare skin disorder characterized by constant scaling, palmoplantar keratoderma, and sometimes erythema, which can be pruritic and may bleed.
  • Parapsoriasis: A group of rare skin disorders that can present with scaly, pruritic lesions, some forms of which may progress to cutaneous T-cell lymphoma.