Differential Diagnosis for Pubic Hair with Square Pale Patches and Hairs Turning White

• Single Most Likely Diagnosis
  • Vitiligo: This condition is characterized by the loss of pigment-producing cells (melanocytes), leading to white patches on the skin. The appearance of square pale patches and the turning of hairs white in the affected area are consistent with vitiligo, especially given its potential to affect any area of the body, including the pubic region.
• Other Likely Diagnoses
  • Tinea versicolor: A fungal infection that can cause changes in skin pigmentation, leading to patches that are lighter or darker than the surrounding skin. While it more commonly affects the trunk, it could potentially affect the pubic area and cause hair to appear white due to the scaling and inflammation associated with the infection.
  • Pityriasis alba: A mild skin condition affecting the face but can occasionally be seen in other areas, characterized by small, round, light patches. It's less likely to cause hair to turn white but could be considered if the patches are primarily pale without significant hair color change.
• Do Not Miss Diagnoses
  • Syphilis (especially secondary syphilis): This sexually transmitted infection can cause a wide range of skin manifestations, including pale patches and hair loss or color changes. Given the potential severity and long-term consequences of untreated syphilis, it's crucial to consider this diagnosis, especially if other symptoms are present.
  • Leprosy (Hansen's disease): A chronic bacterial infection that can cause skin lesions, nerve damage, and hair loss. While rare in many parts of the world, leprosy can lead to significant morbidity if not treated, making it a critical diagnosis not to miss, particularly in individuals with risk factors for exposure.
• Rare Diagnoses
  • Piebaldism: A rare genetic condition characterized by the absence of melanocytes in affected areas of skin and hair, leading to white patches and hair. It's present at birth or appears in infancy, making it less likely if the condition has recently developed.
  • Waardenburg syndrome: Another rare genetic disorder that affects the development of melanocytes, leading to patches of skin and hair that lack pigmentation. Like piebaldism, it's typically identified at birth or in early childhood.