Atopic Dermatitis (Eczema): This is often the most common diagnosis for skin rashes, especially in children and individuals with a history of allergies. It presents with itchy, inflamed skin that can appear anywhere on the body.

Contact Dermatitis: This condition occurs when the skin comes into contact with an allergen or irritant, leading to a rash. It's common in people who work with chemicals or have frequent exposure to potential allergens.
Psoriasis: Characterized by thick, scaly, red patches on the skin, psoriasis is an autoimmune condition that can be triggered by various factors, including stress and certain medications.
Seborrheic Dermatitis: This condition causes scaly patches, red skin, and stubborn dandruff, often affecting oily areas of the body like the face and scalp.

Meningococcemia: Although rare, this condition can present with a rash and is life-threatening if not treated promptly. It's caused by a bacterial infection that can lead to meningitis and sepsis.
Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN): These are severe skin conditions usually triggered by medications, leading to widespread skin necrosis and detachment. They are medical emergencies.
Lyme Disease: Caused by a tick bite, Lyme disease can present with a distinctive "bull's-eye" rash, along with fever, headache, and fatigue. If untreated, it can lead to serious complications.

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.
Dermatomyositis: An inflammatory disease characterized by skin rash and muscle weakness, often associated with underlying autoimmune disorders or cancer.
Kawasaki Disease: A rare condition that mainly affects children, causing fever, rash, swelling of the hands and feet, and other symptoms. It can lead to serious cardiac complications if not treated.