Differential Diagnosis for a 22-year-old Male with Dry, Itchy Skin on Feet and Groin Area

• Single most likely diagnosis:
  • Tinea pedis and tinea cruris (jock itch): Given the description of dry, itchy skin on the feet and groin area, these fungal infections are common in young adults, especially in warm and moist environments. The presentation on the feet, resembling a type of psoriasis, could be due to the inflammatory response to the fungal infection.
• Other Likely diagnoses:
  • Psoriasis: Although the patient mentions it looks like a type of psoriasis on the feet, psoriasis can indeed present with dry, scaly patches. However, the involvement of the groin area might suggest a different or additional diagnosis.
  • Eczema (atopic dermatitis): Eczema can cause dry, itchy skin and can appear in various parts of the body, including the feet and groin area.
  • Contact dermatitis: This is a skin reaction that could occur due to irritants or allergens, leading to dry, itchy skin.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
  • Lymphoma (cutaneous T-cell lymphoma): Although rare, certain types of lymphoma can present with skin lesions that might resemble eczema or psoriasis. It's crucial to consider this in the differential diagnosis due to its severe implications.
  • Infectious diseases (e.g., syphilis, leprosy): Certain infectious diseases can cause skin lesions and should be considered, especially if the patient has been exposed to such pathogens.
• Rare diagnoses:
  • Pityriasis rubra pilaris: A rare skin disorder characterized by constant itching and scaling (exfoliation) of the skin, which could potentially fit the description provided.
  • Keratoderma: A group of rare skin conditions that cause thickening of the skin on the palms and soles, potentially extending to other areas and causing dryness and itchiness.