Psoriasis, seborrheic dermatitis and contact dermatitis cause an itchy scalp with sores, according to WebMD. Psoriasis and seborrheic dermatitis are chronic conditions, while contact dermatitis is an acute condition.
Psoriasis is a common skin condition that causes the accumulation of cells on the skin's surface. The overabundance of cells creates silver, scaly patches and red, itchy, dry patches, which can crack and bleed. There is no cure for psoriasis, and treatment focuses on symptom relief, reports Mayo Clinic. Over-the-counter cortisone cream relieves itching and reduces inflammation. Exposure to sunlight also improves symptoms.
The cause of seborrheic dermatitis is unknown, but it is thought to be a combination of stress, certain medical conditions and medications, genetics and cold, dry weather, states WebMD. When the condition affects an infant, it is called cradle cap. A concurrent diagnosis of acne, depression, an eating disorder, rosacea or psoriasis increases the risk of developing seborrheic dermatitis. Treatments include dandruff shampoos, antifungal products, corticosteroid lotions, prescription shampoos and sulfur products.
Contact dermatitis is an allergic reaction to a substance that has contacted the skin, according to WebMD. It causes a red, itchy rash and can cause painful cracks or blisters when the reaction is severe. When it occurs on the scalp, the reaction is most commonly due to a hair care product. Treatment includes the identification and elimination of the product that caused the reaction when possible. The use of cortisone cream can also reduce or relieve symptoms.