Differential Diagnosis for Rash
- Single most likely diagnosis
- Eczema (Atopic Dermatitis): This is often the most common cause of rash, especially in children and individuals with a history of allergies or asthma. It presents with itchy, inflamed skin that can appear anywhere on the body.
- Other Likely diagnoses
- Contact Dermatitis: This occurs when the skin comes into contact with an irritant or allergen, leading to a rash. It's common and can be caused by a variety of substances, including soaps, detergents, or certain plants.
- Psoriasis: An autoimmune condition characterized by thick, scaly, red patches on the skin. It can appear anywhere but is most common on the elbows, knees, and scalp.
- Allergic Reaction: Can be caused by a wide range of allergens, including foods, medications, or insect bites, leading to hives or a more generalized rash.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningococcemia: A severe infection caused by Neisseria meningitidis, which can present with a rash (petechiae or purpura) and is life-threatening if not treated promptly.
- Rocky Mountain Spotted Fever: A tick-borne illness that can cause a rash, fever, and headache, and can be fatal if not treated with antibiotics.
- Toxic Epidermal Necrolysis (TEN) or Stevens-Johnson Syndrome (SJS): Severe skin conditions usually triggered by medications, leading to widespread skin necrosis and detachment. They are medical emergencies.
- Rare diagnoses
- Pemphigus: A group of autoimmune diseases that cause blistering of the skin and mucous membranes. It's rare but can be life-threatening if not treated.
- Kawasaki Disease: An illness that mainly affects children, causing fever, rash, and swelling of the hands and feet. It can lead to serious heart problems if not treated.
- Lupus: A chronic autoimmune disease that can affect various parts of the body, including the skin, joints, and organs. It can cause a variety of rashes, among other symptoms.