#AskID - Dry Itchy Scalp

Dry itchy scalp
The most common cause of an itchy/scaly scalp is Seborrhoiec dermatitis, better known as dandruff. In infants, the condition is known as cradle cap.
This type of dermatitis occurs in areas containing sebaceous or oil-secreting glands, including the scalp, face (especially eyebrows/sides of the nose) and occasionally the central chest and upper back. It may result in:
• itching
• flaking
• reddened skin of the scalp/face/trunk
• yellow or white scales which sometimes have a greasy texture

Potential causes of seborrhoiec dermatitis include:
• an overgrowth of yeast on the skin
• seasonal changes
• hormonal fluctuations
• stress

Treatment of itchy scalp depends on its cause and may not always be dandruff. There is no cure with a once off treatment for Seborrhoiec dermatitis/Dandruff. It is improved only with maintenance treatment which includes frequent hair washing with special topical agents. These scalp medications work by reducing oil on the scalp or killing the yeast.
Some medications that may be used to treat seborrhoiec dermatitis/dandruff include:
• Antifungal shampoo/pyrithione zinc used regularly 2-3x/week and the foam is required to be left in contact with the skin of the affected areas x 5 minutes
• Keratolytics, such as topical therapies containing salicylic acid which work by lifting the scale (dead skin cells)
• Topical steroids which help to reduce inflammation of the affected areas
If none of the antifungal therapies are helping then it is possibly not seborrhoiec dermatitis. Other scaly/itchy scalp conditions include Psoriasis and Dermatitis such as Atopic dermatitis and Allergic contact dermatitis.

Psoriasis may present classically behind the ears and at the back of the scalp towards the nape of the neck. It can be diffusely spread across the scalp or occur in localised patches consisting of pink skin with thickened silvery scale.

Treatments for this chronic skin condition include tar-based shampoo, topical steroids to reduce itch/inflammation, topical keratolytics containing salicyclic acid to remove the scale and topical tar therapies which have an anti-inflammatory affect on the skin and may be left on the scalp overnight.  
Allergic contact dermatitis may occur as a result of developing an allergy to hair dye (especially dark brown hair dye which contains PPD – Paraphenylenediamine) – this may present more acutely with irritation of the scalp post application of a hair dye and if the reaction is more severe it may also result in swelling of the face including eyelids and lymph nodes in the neck.
Atopic dermatitis is a very common inflammatory condition in children (20% of Irish children) and occurs in up to 11% of adults. This may also occur in the scalp resulting in itchy/scaly scalp. This may be managed with the use of topical steroid scalp applications and also using shampoo which is fragrance free and preservative free, suitable for those with sensitive skin.