Differential Diagnosis for a 2-year-old with a Red, Dry, Scaly Rash on and under the Scrotum

• Single most likely diagnosis:
  • Eczema (Atopic Dermatitis): This is a common condition in children, characterized by dry, itchy, and scaly skin. The location on and under the scrotum is plausible due to the warm, moist environment that can exacerbate eczema symptoms.
• Other Likely diagnoses:
  • Seborrheic Dermatitis: This condition can cause a red, scaly rash and is common in infants and young children. It often affects areas rich in sebaceous glands but can also appear in intertriginous areas like the groin.
  • Contact Dermatitis: This is a reaction to something that has come into contact with the skin, such as soaps, detergents, or certain fabrics. It can cause redness, itching, and scaling.
  • Intertrigo: This is an inflammatory condition of the skin folds, caused by friction, warmth, and moisture. It can lead to a red, scaly rash and is common in areas like the groin.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
  • Scabies: Although less common, scabies can cause a severe, itchy rash and can affect the genital area. It's crucial to consider this diagnosis due to its contagious nature and the need for specific treatment.
  • Sexual Abuse: Any rash in the genital area of a child warrants consideration of sexual abuse, especially if the rash does not fit a common, benign condition. A thorough investigation and possibly a referral to a specialist are necessary.
• Rare diagnoses:
  • Psoriasis: Although rare in young children, psoriasis can cause red, scaly patches. It's less likely but should be considered if the rash does not respond to typical treatments for more common conditions.
  • Lichen Sclerosus: This is a rare condition that can cause thinning and scarring of the skin, often in the genital area. It's more common in girls but can occur in boys, presenting with white, patchy skin that may become scaly.