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Dry, inflamed, itchy scalp is a common condition in children and adults. Red blotches on the scalp may indicate several different disorders, including dermatitis, psoriasis, ringworm, folliculitis, head lice or dandruff, according to MayoClinic.com and Skinsight.com. Several of these conditions can affect other parts of your body as well, so monitor for similar symptoms elsewhere.

Psoriasis

Psoriasis is an inherited skin condition in which the cells of your skin have an accelerated life cycle. Skin cells affected by psoriasis move from lower layers of the skin to the outer layer in four days rather than the usual 28 days. The outer layer of skin becomes thick, flaky and itchy. Scales, crusty fissures and lesions can develop. Psoriasis occurs in 2 percent to 3 percent of the U.S. population, according to SkinSight.com.

Folliculitis

When hair follicles become blocked by dirt, debris and oil, a bacterial infection can develop, causing pimples and inflammation. This condition, called folliculitis, can occur in the scalp, beard or neck. Pseudofolloculitis, more commonly referred to as razor bumps, occurs in the beard or on the neck.

Dermatitis

Dermatitis, a skin condition characterized by inflammation, redness, swelling and sometimes skin lesions, can affect skin almost anywhere on your body, including your scalp. Various forms of dermatitis, each associated with particular causal conditions or symptoms, can contribute to inflammation of the scalp. Atopic dermatitis, a chronic, itchy rash, occurs episodically, and frequently co-occurs with allergies or asthma. Dermatitis can be made worse by irritants including skin products, soap, creams and metals, according to MayoClinic.com. Food allergies may also contribute to dermatitis, reports the American Academy of Family Physicians.

Dandruff

Dandruff is a form of dermatitis that occurs commonly in children and adults. Marked by flaking and sometimes red inflammation of the skin, it occurs in areas that have abundant oil glands, such as the scalp, face and upper part of the trunk. Like psoriasis, overproduction and accelerated movement of skin cells to the surface of the skin cause symptoms. Common skin yeast and hormones contribute to the development of dandruff. The cold dry air of winter and harsh shampoos can exacerbate symptoms. Dandruff can often be treated simply by using medicated shampoos.

Ringworm

Ringworm is a contagious fungal infection of the scalp that, despite its ominous sounding name, does not involve any worms. It causes a round patch of inflamed, itchy skin which often has a round patch of healthier scalp in the middle, forming the appearance of a ring. It is treated with a prescription fungicide you can obtain through your doctor.

Head Lice

Head lice are highly contagious, spread through direct or indirect contact with others who are infected. Head lice are tiny insects that feed on blood. The eggs, or nits, of the louse can survive for 10 days in hats, scarves or any cloth material that has had contact with an infected person. Treatment requires the use of medicated shampoos and daily washing of sheets, pillow cases, hats and other infected material.

Treatment

Each condition requires specific treatment. Dandruff and mild dermatitis can be treated effectively through home remedies, medicated shampoo or over-the-counter medications. While folliculitis treatment can involve careful hygiene, dermatitis and psoriasis can be made worse by frequent shampooing. If you have any questions about the cause of skin blotches, speak with your doctor. You may be able to treat the condition at home, but you might need some help figuring out what exactly you are treating.