Differential Diagnosis for Red Itchy Skin Under Eyes and on Neck

Single Most Likely Diagnosis

• Atopic Dermatitis (Eczema): This condition is characterized by itchy, inflamed skin and is common in areas like the face, neck, and hands. It often worsens in heat, which aligns with the symptoms described.

Other Likely Diagnoses

• Contact Dermatitis: An allergic reaction or irritation from substances like cosmetics, soaps, or jewelry can cause red, itchy skin under the eyes and on the neck. Heat can exacerbate the symptoms.
• Seborrheic Dermatitis: This condition causes scaly patches, red skin, and stubborn dandruff, often affecting oily areas of the body like the face. It can worsen in hot weather.
• Heat Rash (Miliaria): Directly related to overheating, heat rash can cause red, itchy bumps and is more common in warm weather.

Do Not Miss Diagnoses

• Angioedema: A severe, potentially life-threatening condition that can cause swelling, redness, and itching, often in response to an allergen. It requires immediate medical attention.
• Stevens-Johnson Syndrome: A rare but serious disorder of the skin and mucous membranes, usually a reaction to medication or infection. It can start with symptoms similar to those described but quickly progresses to more severe manifestations.

Rare Diagnoses

• Dermatomyositis: An inflammatory disease characterized by skin rash and muscle weakness. The rash can appear on the face, including under the eyes, and on the neck.
• Pellagra: A disease caused by a lack of vitamin B3 (niacin), which can lead to dermatitis, diarrhea, dementia, and potentially death if left untreated. The dermatitis can be exacerbated by sunlight and heat.