Differential Diagnosis for Red Rash at the Back of Neck in Infant

Single Most Likely Diagnosis

• Eczema (Atopic Dermatitis): This is a common condition in infants, often presenting as a red, itchy rash, and can appear at the back of the neck. Its prevalence and typical presentation in infants make it a likely first consideration.

Other Likely Diagnoses

• Contact Dermatitis: This could be due to an allergic reaction or irritation from clothing, detergents, or other substances coming into contact with the skin at the back of the neck.
• Seborrhoeic Dermatitis: Also known as cradle cap when it affects the scalp, but it can also appear on other oily areas of the body, including the back of the neck, causing a red, oily, scaly rash.
• Impetigo: A contagious skin infection that can cause red sores on the skin, which can appear anywhere on the body, including the back of the neck.

Do Not Miss Diagnoses

• Meningitis: Although less common, a rash at the back of the neck in an infant could be a sign of meningitis, especially if accompanied by other symptoms such as fever, vomiting, or lethargy. Meningitis is a medical emergency.
• Kawasaki Disease: This condition can cause a rash, fever, and swelling, particularly of the hands and feet, but a rash can also appear on other parts of the body. It's a serious condition that requires prompt treatment.

Rare Diagnoses

• Staphylococcal Scalded Skin Syndrome (SSSS): A rare but serious condition caused by staphylococcal toxins that typically affects infants and young children, causing widespread blistering and peeling of the skin.
• Congenital Syphilis: Can cause a variety of skin rashes, including at the back of the neck, among other systemic symptoms. It's essential to consider this in infants born to mothers with untreated syphilis.