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Seborrheic Dermatitis (dandruff)
What is a seborrheic dermatitis?
Seborrheic dermatitis is a common skin problem of unknown cause that presents with dandruff, greasy scale, redness and slight itching. It usually affects any of the following: scalp, central face, eyebrows, corners of nose, central chest, behind ears and in groin. It occurs at any age and both in females and males. It is more common in babies and older individuals as well as any individual with diseases of nervous system and those with HIV/AIDS.
Does this mean that I have a seborrheic dermatitis if I have dandruff?
Yes, probably it does. However, if the dandruff is thicker and more sticking to the scalp then it could be a psoriasis.
What is the cause of a seborrheic dermatitis?
The exact cause is unknown, but here are some possible causes:
- Allergic (i.e. excessive) response of our immune system to skin yeast (Pityrosporum) that almost everyone has on the skin, or
- Direct injury to the skin by the skin yeast (Pityrosporum)
- Cold and dry weather
- Some medicines (interferon, lithium, psoralen)
- Some medical conditions such as diseases of nervous system, weak immune system (HIV/AIDS)
- Your genes
What is the treatment for a seborrheic dermatitis?
Since the cause is unknown, there is no cure for a seborrheic dermatitis, but there are medicines that will keep it invisible. You can always start with over-the-counter shampoos and washes such as selenium sulfide 1% shampoo (brand names: Selsun and Exelderm), and zinc pyrithione (brand names: Head and Shoulders, DHS zinc). However, if these over-the-counter treatments are not helpful, then anti-yeast creams and shampoos (medications that kill the yeast on the skin) and/or corticosteroid ointments, creams or liquids (medications that reduce skin allergic immune response) should be tried. We usually start with prescription anti-yeast shampoos on the scalp, face and body such as ketoconazole 2% shampoo (brand name: Nizoral), selenium sulfide 2.25% shampoo, or ciclopirox olamine1% shampoo (brand name: Loprox) with every shower for 2-4 weeks with instructions to leave the shampoo on for about 5-10 minutes before rinsing, then once weekly or every two weeks as a maintenance. In addition we start anti-yeast cream such as ketoconazole 2% cream (brand name: Nizoral) or ciclopirox 0.77% cream (brand name: Loprox) twice daily. If above did not completely make the seborrheic dermatitis invisible, then we add corticosteroid creams and liquids such as fluocinolone scalp liquid (brand name: Synalar) twice daily for 2 weeks, then 1-3 times weekly on scalp, and hydrocortisone 2.5% cream or desonide 0.05% cream 1-3 times weekly on any remaining rash. If you cannot tolerate corticosteroid creams another option is pimecrolimus 1 % cream (brand name: Elidel) twice daily; however, we have rarely needed to prescribe this cream to our patients. This should be good enough for the vast majority of our patients, but sometimes we need to use stronger treatments.