Differential Diagnosis for Sinus Congestion and Red Rash Across Face

• Single Most Likely Diagnosis
  • Allergic Rhinitis: This is the most likely diagnosis, as the patient's symptoms of sinus congestion followed by a red rash across the face could be indicative of an allergic reaction, possibly to pollen, dust, or other environmental allergens. The rash could be a manifestation of the allergic response.
• Other Likely Diagnoses
  • Acne Rosacea: This condition can cause redness and rash across the face, often accompanied by symptoms that might be mistaken for sinus congestion, such as facial flushing and swelling.
  • Contact Dermatitis: Direct contact with an allergen or irritant could cause a red rash on the face, and if the allergen or irritant also affects the nasal passages, it could lead to sinus congestion.
  • Urticaria (Hives): Although hives are typically itchy and can appear anywhere on the body, they could initially present on the face and be accompanied by sinus congestion if the cause is an allergic reaction.
• Do Not Miss Diagnoses
  • Lupus: Systemic lupus erythematosus can cause a butterfly-shaped rash across the cheeks and nose, which might be accompanied by sinus congestion among its myriad other symptoms. Missing this diagnosis could lead to significant morbidity.
  • Cellulitis: A bacterial infection of the skin that could start as redness and swelling, potentially accompanied by sinus congestion if the infection spreads to the facial tissues. It requires prompt antibiotic treatment.
  • Granulomatosis with Polyangiitis (formerly known as Wegener's Granulomatosis): This is a rare autoimmune disorder that can cause sinus congestion and a rash, among other symptoms. It's critical to diagnose early due to its potential for severe complications.
• Rare Diagnoses
  • Sarcoidosis: A condition that can cause skin rashes and sinus congestion among its many possible manifestations. It's an autoimmune disease that can affect multiple parts of the body.
  • Erythema Multiforme: A skin condition characterized by target lesions, which could appear as a rash on the face. It can be triggered by infections or medications and might be accompanied by mucosal involvement, including the nasal mucosa.