Scalp Psoriasis Vs. Dandruff: What Are the Differences?

Symptoms of scalp psoriasis and dandruff — their similarities and differences — are outlined in the table below.

All forms of psoriasis, including scalp psoriasis, are caused by an overactive immune system, but the reason for this immune system overactivity is not known. 

Risk factors for developing scalp psoriasis include:

• Family history 
• Use of certain medicines, including blood pressure medications, lithium, and antimalarial drugs
• Certain types of infections, such as strep
• Obesity
• Smoking

Triggers for scalp psoriasis flares include:

• Stress
• Skin injury, including scratches, scrapes, cuts, bug bites, sunburns, and vaccinations 
• Excess alcohol consumption
• Allergies
• Certain foods
• Illness, such as ear infection, bronchitis, tonsillitis, or respiratory infection
• Exposure to secondhand smoke
• Weather, especially cold and dry weather 
• Environmental factors 

The exact cause of dandruff (seborrhea) is believed to be due to an inflammatory reaction to a type of yeast (Malassezia globosa) that naturally lives on the skin. Most people have this microbe on their skin, and about half of all people are sensitive to it. 

Risk factors for developing dandruff include:

• Dry skin
• Sensitivity to hair products
• Skin irritation
• Skin conditions such as eczema or psoriasis 
• Genetics 
• Stress
• Certain medications
• Hormonal changes
• Certain illnesses such as Parkinson’s disease and diseases that affect the immune system, such as HIV or AIDS
• Dandruff is not caused by allergies or poor hygiene. 

Both scalp psoriasis and dandruff are usually diagnosed with a physical examination of the scalp. 

If the diagnosis is uncertain, a small sample of skin may be taken (a biopsy) may be taken to help confirm a diagnosis or to help rule out other conditions.

It is important to get a diagnosis for scalp psoriasis versus dandruff, because in some cases, scalp psoriasis may require prescription medications. 

Scalp psoriasis can be difficult to treat. The goal of treatment for scalp psoriasis is to relieve symptoms. 

Treatments to help get rid of psoriasis on the scalp include: 

• Topical treatments, such as creams and ointments
  • Over-the-counter (OTC) topical treatments: The National Psoriasis Foundation (NPF) has a Seal of Recognition program that recognizes over-the-counter products intended to be non-irritating and safe for people with psoriasis
  • Look for products such as shampoos that contain:
    • Salicylic acid to help soften plaques and scales and remove scales from the skin
    • Coal tar or wood tar, to help slow skin cell growth and reduce inflammation, itching, and scaling
    • Scale lifters (keratolytics) with active ingredients such as salicylic acid, urea, lactic acid, or phenol to help loosen and remove scale, and allow medications to reach the psoriasis plaques
    • Aloe vera, jojoba, zinc pyrithione, and capsaicin to soothe, moisturize, remove scale, or relieve itching 
    • Anti-itch treatments such as calamine, hydrocortisone, camphor, benzocaine, diphenhydramine hydrochloride, and menthol (may increase irritation and dryness)
    • Coverings such as plastic wrap, cellophane, waterproof dressing, cotton socks, or a nylon suit may be applied over topical treatments to help increase effectiveness 
  • Prescription topical treatments
    • Anthralin
    • Calcipotriene (Dovonex) 
    • Calcipotriene and betamethasone (Taclonex)
    • Calcitriol (Vectical)
    • Steroids
    • Tazarotene (Tazorac)
• Systemic treatments
  • Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen (Advil, Motrin) for inflammation 
  • Biologics and biosimilars
    • Tumor necrosis factor-alpha (TNF-alpha) inhibitors 
    • Interleukin 12 and 23 (IL-12, IL-23) inhibitors 
    • Interleukin 17 (IL-17) inhibitors 
    • T-cell inhibitors 
    • Interleukin 23 (IL-23) inhibitors 
  • Disease-modifying antirheumatic drugs (DMARDs) 
  • Traditional oral systemics
    • Acitretin (Soriatane)
    • Cyclosporine
    • Methotrexate
    • Off-label systemics, including hydroxyurea (Hydrea), isotretinoin, mycophenolate mofetil, sulfasalazine, and 6-Thioguanine 
• Phototherapy (light therapy)
  • Ultraviolet light B (UVB): broad band and narrow band
  • Psoralen + UVA (PUVA) 

Treatment of dandruff (seborrhea) includes:

• Frequent shampooing or longer lathering
• Avoiding use of hair spray or hair pomades
• Dandruff hair care
  • Use of shampoos with antifungal or antiseptic properties containing salicylic acid, coal tar, sulfur, or zinc; selenium sulfide (2.5%), ketoconazole, and ciclopirox 
    • Follow instructions on the dandruff shampoo bottle because each type of active ingredient may require different application
    • Note that coal tar shampoos can discolor blonde, grey, or white hair, and can also make the scalp sensitive to sunlight so it is important to wear a hat if using this type of dandruff shampoo
  • Use of conditioner with zinc, 0.01% fluocinolone, and acetonide topical oil
  • Applying tar, bath oil, Baker’s P&S solution, or Derma-Smoothe F/S oil overnight to loosen scales may be helpful