Differential Diagnosis for Eczematous Lesions and Scalp Hair Loss

The patient's presentation of eczematous-like lesions disseminated all over the body, associated with post-inflammatory hyperpigmentation, erythematous patches and plaques, and papules on the face, along with scalp hair loss, suggests a complex dermatological condition. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Discoid Lupus Erythematosus (DLE): This condition is characterized by chronic, scarring, discoid lesions on the scalp, face, and ears, which can lead to hair loss. The presence of erythematous patches, plaques, and post-inflammatory hyperpigmentation supports this diagnosis. The recession of the hairline with preserved hair follicles is also consistent with DLE.

• Other Likely Diagnoses

  • Psoriasis: Psoriasis can present with erythematous plaques and papules on the body and scalp, leading to hair loss. However, the presence of eczematous-like lesions and the specific pattern of hair loss might make psoriasis less likely.
  • Seborrheic Dermatitis: This condition can cause erythematous patches and plaques on the face and scalp, leading to hair loss. It often involves the central area of the scalp and can cause a receding hairline.
  • Alopecia Areata: While primarily known for causing patchy hair loss, alopecia areata can sometimes be associated with erythematous patches and might be considered, especially if the hair loss is the primary concern.

• Do Not Miss Diagnoses

  • Systemic Lupus Erythematosus (SLE): Although less likely than DLE given the description, SLE can cause a wide range of skin manifestations, including those described, and is critical not to miss due to its systemic implications.
  • Dermatomyositis: This condition can present with skin manifestations similar to those described, including erythematous patches and plaques, and is associated with muscle weakness. It's crucial to consider due to its potential for significant morbidity.

• Rare Diagnoses

  • Sarcoidosis: This condition can cause skin lesions, including erythematous patches and plaques, and can lead to hair loss. It's less common but should be considered in the differential due to its systemic nature.
  • Lichen Planopilaris: A condition that causes inflammation and scarring hair loss, often on the scalp. It might present with erythematous patches and post-inflammatory hyperpigmentation, making it a rare but possible diagnosis to consider.

Each of these diagnoses requires careful consideration of the patient's full clinical presentation, including any additional symptoms or findings not mentioned, and may necessitate further diagnostic testing to confirm.