Differential Diagnosis for the 11-year-old Patient
Single Most Likely Diagnosis
- Atopic Dermatitis (Eczema): This is the most likely diagnosis given the patient's symptoms of a red, itchy rash that comes and goes, with small raised papules on the bilateral arms. The absence of changes in soap or detergent and the presence of small patches on the arms also support this diagnosis, as atopic dermatitis is a chronic condition characterized by dry, itchy skin and is common in children.
Other Likely Diagnoses
- Contact Dermatitis: Although the mother denies any changes in soap or detergent, contact dermatitis is still a possibility, especially if the patient has come into contact with a new substance that is causing an allergic reaction. The presence of small raised papules on the arms could be consistent with an allergic contact dermatitis.
- Insect Bite Reaction: The itchy, red rash and small raised papules could also be consistent with an insect bite reaction, especially if the patient has been outdoors or exposed to insects.
- Keratosis Pilaris: This is a common condition in children, characterized by small, rough patches on the skin, often on the arms. While it is not typically itchy, it could be considered in the differential diagnosis.
Do Not Miss Diagnoses
- Bullous Pemphigoid: Although rare in children, bullous pemphigoid is a serious condition that can present with itchy, red skin and blisters. It is essential to consider this diagnosis to avoid missing a potentially life-threatening condition.
- Stevens-Johnson Syndrome: This is a rare but serious condition that can present with a rash, blisters, and skin peeling. It is often associated with medication use or infection, and prompt recognition and treatment are critical to prevent serious complications.
Rare Diagnoses
- Pityriasis Rosea: This is a rare condition characterized by a rash with small, raised papules, often on the arms and trunk. It is typically seen in older children and young adults.
- Guttate Psoriasis: This is a rare form of psoriasis that can present with small, raised papules on the arms and trunk. It is often seen in children and young adults, and can be triggered by a streptococcal infection.