Differential Diagnosis for Burning Sensation after Rash Treatment

The patient's symptoms of a burning sensation after being treated for a rash on their back can be approached by considering the following differential diagnoses:

• Single most likely diagnosis
  • Post-herpetic neuralgia: This condition is a possible complication of shingles (herpes zoster), which could have presented as a rash. The burning sensation is a common symptom of post-herpetic neuralgia, especially if the rash was not properly managed or if the patient had an underlying condition that predisposed them to this complication.
• Other Likely diagnoses
  • Contact dermatitis: The treatment for the initial rash could have contained ingredients that the patient is allergic to, leading to contact dermatitis and a burning sensation.
  • Eczema (atopic dermatitis): If the patient has eczema, the initial rash and subsequent treatment could have exacerbated the condition, leading to a burning sensation.
  • Psoriasis: Similar to eczema, if the patient has psoriasis, the treatment for the rash could have worsened the condition, causing a burning sensation.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Sepsis: Although less likely, if the initial rash was a sign of an underlying infection that was not properly treated, the patient could be at risk for sepsis, which is a life-threatening condition.
  • Toxic epidermal necrolysis (TEN): This is a severe skin condition usually triggered by medications. It can present with a burning sensation and is life-threatening, making it a diagnosis that should not be missed.
• Rare diagnoses
  • Complex regional pain syndrome (CRPS): This is a rare condition characterized by burning pain and is usually associated with trauma or injury. It could be considered if other diagnoses are ruled out and the patient's symptoms persist.
  • Neuropathic pain due to other causes: Other rare neuropathic conditions could cause a burning sensation, such as nerve damage from diabetes or certain vitamin deficiencies, although these would be less directly related to the treatment of a rash.