Differential Diagnosis for a 22-year-old Male with a Red and Itchy Scalp

Single Most Likely Diagnosis

• Seborrheic Dermatitis: This condition is characterized by a red, itchy, and flaky scalp, often associated with oily skin. It's a common condition in young adults, making it the most likely diagnosis given the patient's age and symptoms.

Other Likely Diagnoses

• Psoriasis: An autoimmune condition that can cause red, itchy patches on the scalp. It's less common than seborrheic dermatitis but still a plausible diagnosis.
• Dandruff (Pityriasis Simplex): A mild form of seborrheic dermatitis, characterized by flakes on the scalp without significant redness or inflammation.
• Contact Dermatitis: An allergic reaction or irritation from hair care products, which could cause redness and itching on the scalp.
• Tinea Capitis (Ringworm of the Scalp): A fungal infection that can cause redness, itching, and hair loss on the scalp.

Do Not Miss Diagnoses

• Scalp Cellulitis or Abscess: Bacterial infections that can cause redness, swelling, and pain on the scalp. These conditions require prompt antibiotic treatment to prevent serious complications.
• Kerion: A severe form of tinea capitis that can cause significant inflammation and potentially lead to scarring if not treated properly.

Rare Diagnoses

• Pityriasis Amiantacea: A rare condition characterized by thick, yellow scales on the scalp, often associated with psoriasis or seborrheic dermatitis.
• Lichen Planopilaris: An autoimmune condition that can cause inflammation and scarring on the scalp, leading to hair loss.
• Discoid Lupus Erythematosus: A chronic autoimmune condition that can cause skin lesions and scarring on the scalp, among other areas.