Differential Diagnosis for a Condition that Glows Green Underneath the Wood's Lamp

• Single most likely diagnosis:
  • Tinea versicolor: This condition is caused by a fungal infection of the skin, and it is known to fluoresce a yellowish-green color under a Wood's lamp due to the presence of the fungus Malassezia.
• Other Likely diagnoses:
  • Erythrasma: A bacterial infection that can cause a greenish fluorescence under a Wood's lamp, typically found in the intertriginous areas.
  • Pseudomonas infection: Certain species of Pseudomonas bacteria can produce a greenish pigment called pyocyanin, which may fluoresce under a Wood's lamp.
• Do Not Miss diagnoses:
  • Hyperbilirubinemia: Although less likely to cause a green glow specifically, severe jaundice can lead to a yellowish discoloration of the skin, which might be misinterpreted under certain lighting conditions. Missing this diagnosis could be critical due to the potential underlying liver or hemolytic disorders.
• Rare diagnoses:
  • Porphyrias: A group of disorders that can lead to the accumulation of porphyrins in the skin, which may cause it to glow under a Wood's lamp. However, the color is more typically pink or red rather than green.
  • Certain chemical or drug exposures: Some substances can cause the skin to fluoresce, but these are rare and would typically be associated with a known exposure history.