Differential Diagnosis for Rash that Spares Palms and Soles

• Single most likely diagnosis
  • Atopic Dermatitis (Eczema): This is a common condition characterized by itchy, inflamed skin that typically spares the palms and soles. It often starts in childhood and can be associated with other atopic diseases like asthma and allergic rhinitis.
• Other Likely diagnoses
  • Psoriasis: While psoriasis can occasionally affect the palms and soles, many forms of the disease spare these areas, presenting instead on elbows, knees, scalp, and lower back.
  • Seborrheic Dermatitis: This condition causes scaly patches, red skin, and stubborn dandruff due to an oily scalp. It can also appear on oily areas of the body, such as the face, but typically spares the palms and soles.
  • Contact Dermatitis: This is a type of inflammation of the skin that occurs when the skin comes into contact with an irritant or allergen. It can appear anywhere on the body, often sparing the palms and soles unless the causative agent directly contacts these areas.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Syphilis (Secondary): In its secondary stage, syphilis can cause a rash that often involves the trunk and extremities but typically spares the palms and soles. Missing this diagnosis can lead to serious complications if left untreated.
  • Lyme Disease: The rash associated with Lyme disease (erythema migrans) usually appears as a single lesion, but in some cases, multiple lesions can occur, potentially sparing the palms and soles. Early diagnosis is crucial for effective treatment.
• Rare diagnoses
  • Pityriasis Rubra Pilaris (PRP): A rare skin disorder that causes constant inflammation and scaling (exfoliation) of the skin. While it can involve the palms and soles, some forms may spare these areas.
  • Keratosis Pilaris: A harmless condition that causes small, rough, sandpapery patches on the skin, typically on the arms, legs, buttocks, and cheeks, and usually spares the palms and soles.