• Irritants in shampoo may contribute to scalp itching.bubble image by saied shahinkiya from Fotolia.com
  
  Head itching results from a variety of disorders of varying seriousness on the scalp. Specific symptoms accompanying the itching indicate which condition affects the sufferer. Simple conditions such as unwashed hair and more serious problems like fungal infections and psoriasis can cause scalp itch. Sufferers should see a dermatologist for chronic or intense scalp irritation that does not respond to home treatment.
  
  

Washing Frequency

• Hair should be washed at least once a week to avoid itchy build-up of dandruff and sebaceous oils. Yet, a dry, itchy scalp can also result from too frequent washing and stripping of those moisturizing oils. Sufferers of itchy scalp should adjust the number of times per week they wash their scalp until they find the frequency that controls itchiness.
  
  

Irritating Shampoo

• Certain kinds of shampoo contribute to itchy scalp. Many shampoos contain potentially irritating ingredients such as sodium laureth sulfate and sodium lauryl sulfate. To avoid irritation, sufferers should use shampoos that do not contain harsh ingredients. Shampoos also may possess an alkaline pH value which neutralizes the scalp's natural acidic pH level. Sufferers should purchase low-pH shampoo or test their shampoos using pH strips. Bar soap contains lye, a highly alkaline substance. Sufferers of itchy scalp should never wash their hair with bar soap.
  
  

Scalp Psoriasis

• Psoriasis affects skin chronically throughout the skin's surface. Some psoriasis sufferers, however, only experience the condition on the scalp. Psoriasis causes dry, flaky, itchy and scaly skin and causes irritation exceeding that of simple scalp dryness. Affected areas appear red and may crack or bleed. Countless treatments are available for psoriasis. Sufferers should consider seeing a dermatologist to determine which treatment is right for them.
  
  

Seborrheic Dermatitis

• Unlike psoriasis, seborrheic dermatitis affects the scalp more often than the rest of the body. Seborrheic dermatitis also causes dry, itchy and flaky skin on the scalp. Doctors differentiate the condition from psoriasis by analyzing identifying characteristics. For example, seborrheic dermatitis results in yellow or white flakes on the scalp that come off easily, whereas psoriasis flakes appear silvery white and may cause the skin to bleed when removed.
  
  

Head Lice

• Parasitic head lice live on the scalp and lay eggs on the hair shaft. Lice bite the scalp to consume the blood of their host. These bites cause significant irritation and itching. Those with an itchy scalp suspecting head lice should ask a friend to look at the scalp for signs of adult lice and small white eggs.
  
  

Ringworm

• Ringworm does not refer to an actual worm. Rather, the name pertains to the circular formation this fungus takes when present on the skin. Sufferers of ringworm will notice this itchy reddish ring on the scalp accompanied by hair loss in the affected area.