Differential Diagnosis for a 44-year-old Woman with Maculopapular Rash and Recent Blepharitis

• Single Most Likely Diagnosis
  • Rosacea: This condition is characterized by a maculopapular rash, often accompanied by symptoms like blepharitis, and typically affects the central face, including the neck in some cases. The presence of blepharitis, which is inflammation of the eyelids, is a common feature in rosacea, making it a strong candidate for the single most likely diagnosis.
• Other Likely Diagnoses
  • Seborrheic Dermatitis: This is a skin condition causing a red, itchy, and flaky rash, typically on the scalp, but it can also appear on oily areas of the body such as the face and neck. It can sometimes be associated with blepharitis.
  • Contact Dermatitis: An allergic reaction or irritation caused by something that has come into contact with the skin, which could explain both the maculopapular rash and the blepharitis if the causative agent also came into contact with the eyes.
  • Atopic Dermatitis (Eczema): Although more common in children, atopic dermatitis can persist into adulthood and is characterized by itchy, inflamed skin that can appear anywhere on the body, including the neck, and can be associated with blepharitis.
• Do Not Miss Diagnoses
  • Lyme Disease: Caused by a tick bite, Lyme disease can present with a distinctive rash (erythema migrans) and can be accompanied by other symptoms such as fever, headache, and fatigue. It's crucial to consider this diagnosis due to its potential for serious complications if left untreated.
  • Syphilis: The secondary stage of syphilis can cause a maculopapular rash on the trunk and extremities, including the neck, and can also involve the eyes, leading to symptoms like blepharitis. Given the potential severity of untreated syphilis, it's a critical diagnosis not to miss.
• Rare Diagnoses
  • Sarcoidosis: A condition that can affect multiple parts of the body, including the skin and eyes, causing rashes and uveitis or blepharitis. While less common, its potential impact on various body systems makes it a diagnosis worth considering in complex cases.
  • Kawasaki Disease: Although primarily seen in children, Kawasaki disease can very rarely occur in adults and is characterized by fever, rash, swelling of the hands and feet, and conjunctivitis, which could potentially be confused with blepharitis. Its inclusion as a rare diagnosis is due to its low likelihood but high importance due to potential cardiac complications.