Differential Diagnosis for 55-year-old Female Patient with Bilateral Lower Limb Red Rash after Umrah

• Single most likely diagnosis:
  • Contact dermatitis: This is a common condition that can occur after exposure to new substances, such as soaps, detergents, or other irritants that the patient may have encountered during Umrah. The sudden onset of a bilateral lower limb red rash supports this diagnosis.
• Other Likely diagnoses:
  • Cellulitis: This is a bacterial skin infection that can cause redness, swelling, and warmth of the skin. Travel and increased physical activity during Umrah may have predisposed the patient to this condition.
  • Eczema (atopic dermatitis): This chronic condition can cause itchy, inflamed skin and may have been exacerbated by environmental factors or stress during Umrah.
  • Allergic reaction: The patient may have had an allergic reaction to a new medication, food, or substance encountered during travel.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Deep vein thrombosis (DVT): Prolonged travel and immobility during Umrah increase the risk of DVT, which can cause leg redness and swelling. Although less likely, missing this diagnosis could be fatal.
  • Necrotizing fasciitis: This rare but life-threatening condition is characterized by rapid progression of infection and can cause redness, swelling, and pain in the affected limb.
• Rare diagnoses:
  • Erythema nodosum: This condition causes red, painful nodules on the skin, often on the lower legs, and can be triggered by various factors, including infections, medications, or systemic diseases.
  • Vasculitis: This inflammation of the blood vessels can cause a range of symptoms, including skin rashes, and may be related to an underlying autoimmune or inflammatory condition.