Pityriasis capitis

Overview

Dandruff is the excessive flaking of dead skin that forms on the scalp, eyebrows, forehead and elsewhere on the body. As it is natural for skin cells to die and flake off, a small amount of flaking is normal and in fact quite common. Some people, however, either chronically or as a result of certain triggers, experience an unusually large amount of flaking, which can also be accompanied by redness and irritation. Most cases of dandruff can be treated with specialized shampoos.

Symptoms

  • Flaking white scales
  • Reddish patches of skin with flakes on top
  • Itchiness

Dandruff can also be a symptom of other conditions such as seborrheic dermatitis, a condition where people get inflammation and scaling typically on the ears, scalp, along the sides of the nose, and eyebrows. Rare causes of dandruff may include psoriasis, fungal infection or head lice.

Causes

  • Infrequent shampooing
  • Oily skin
  • Use of irritating hair products
  • Skin conditions such as acne, psoriasis, rosacea
  • Candida, a yeast-like organism may also cause dandruff

As skin grows, epidermal cells are pushed outward where they eventually die and flake off. In most people, these flakes of skin are too small to be visible. However, certain conditions cause cell turnover to be unusually rapid, especially common in the scalp. In people with dandruff, skin cells may die and be replaced about once every two weeks, as opposed to around once a month in people without dandruff. The result is that dead skin cells are shed in large clumps, which appear as small, white or grayish patches. Fungus is the most common cause for this. Other causes include:

  • Dry skin
  • Skin conditions such as psoriasis and seborrheic dermatitis
  • Overactive sebaceous glands
  • Food allergies
  • Excessive perspiration
  • Stress
  • Alkaline soaps
  • Yeast infections

Treatment

Excessive scratching should be avoided. Scratching to the point of causing breaks in the skin can increase the risk for infections.

The appearance of flakes can be reduced, especially in those who suffer from only a mild case of dandruff, by proper hair care. Some people mistakenly avoid washing their hair, believing that the drying effect of shampoo will worsen their dandruff. By washing the hair regularly, however, dead skin is removed before it can build up into larger, more noticeable flakes. Using acid-based shampoos helps restore acidity to the scalp, breaking down oils and preventing dead skin cells from collecting into visible clumps. However, shampoos with milder medication, or shampoos that are not marked to treat seborrheic dermatitis, may have little to no effect on redness and irritation. Nizoral is an example of a shampoo that works for seborrheic dermatitis, often it is required only 2 times a week or just with flares. Over the counter cortisone cream can help with the redness or inflammation.

Dandruff varies from person to person. It may be necessary to try various shampoos with different active ingredients (selenium sulfide, tar, salicylic acid, and zinc pyrithione, ketoconazole) to find the best suited for any one individual. Also, an individual may find that alternating between different treatments will be more effective than sticking with a single treatment, which can become less effective over time.

Severe forms of dandruff, particularly if accompanied by flaking or scaling on other parts of the body, should be treated by a dermatologist.