Differential Diagnosis for Oral Lichen Planus and Nail Changes

The patient presents with a history of oral lichen planus and is now experiencing changes in their toenails that resemble lichen planus. Given the dermatological and potential systemic implications, a comprehensive differential diagnosis is crucial.

• Single Most Likely Diagnosis

  • Lichen planus of the nails: This is the most straightforward diagnosis given the patient's history of oral lichen planus. Lichen planus can affect the skin, mucous membranes, and nails, leading to changes such as thinning, ridging, or scarring of the nails.

• Other Likely Diagnoses

  • Psoriasis: This condition can cause nail changes similar to those seen in lichen planus, including pitting, thickening, or separation of the nail from the nail bed.
  • Eczema (atopic dermatitis): Eczema can lead to nail changes, although these are less common than skin manifestations. The nail changes might include thickening, brittleness, or ridging.
  • Alopecia areata: While primarily known for causing hair loss, alopecia areata can also affect the nails, leading to changes such as ridging, brittle nails, or nail loss.

• Do Not Miss Diagnoses

  • Systemic lupus erythematosus (SLE): SLE is an autoimmune disease that can cause a wide range of symptoms, including skin rashes, joint pain, and nail changes. It's crucial to consider SLE because of its potential for serious systemic complications.
  • Sjögren's syndrome: This autoimmune disorder can cause dryness in the eyes and mouth but can also be associated with skin and nail changes. It's a "do not miss" diagnosis due to its potential to cause significant morbidity.
  • Lichen striatus: A rare condition that can cause skin and nail changes, often in a linear pattern. While less common, it's essential to consider due to its distinct presentation and potential for nail involvement.

• Rare Diagnoses

  • Keratoderma: A group of rare genetic disorders that can cause thickening of the skin on the palms and soles and may also affect the nails.
  • Yellow nail syndrome: A rare condition characterized by thickening and yellowing of the nails, often associated with lymphedema and respiratory problems.
  • Nail changes associated with internal malignancies: Certain cancers can cause nail changes, such as clubbing or thinning of the nails. While rare, these changes can be an early sign of an underlying malignancy.

Given the complexity and potential systemic implications of these diagnoses, a thorough evaluation by a dermatologist or another relevant specialist is essential. The involvement of podiatry, as suggested by the endodontist, may provide interim care but should not replace a comprehensive dermatological assessment.