Psoriasis of the Scalp

Understanding Psoriasis

Psoriasis is a non-contagious, chronic autoimmune disease that affects approximately 2-3% of the global population. It is characterized by an accelerated life cycle of skin cells. Normally, skin cells mature and shed over a period of about 28 to 30 days. In individuals with psoriasis, this process is dramatically sped up, with new skin cells being produced in as little as 3-4 days. This rapid turnover leads to a buildup of cells on the skin's surface, forming thick, silvery scales and red patches, often accompanied by itching, burning, and discomfort.

While psoriasis can manifest anywhere on the body, the scalp is a very common location, affecting about 50-80% of individuals with the condition. Scalp psoriasis can range from mild, with fine, flaky scales, to severe, involving thick, crusted plaques that cover the entire scalp and may extend to the forehead, neck, and behind the ears.

Causes and Triggers

Psoriasis is an autoimmune disease, meaning the body's immune system mistakenly attacks healthy cells. In this case, T cells, a type of white blood cell, become overactive and trigger inflammation and rapid skin cell growth. The exact cause of this immune system malfunction is not fully understood, but it is believed to be a combination of genetic predisposition and environmental factors.

Genetic Predisposition

Around one-third of people with psoriasis have a family history of the condition, indicating a genetic link. Specific genes have been identified that increase an individual's susceptibility to psoriasis.

Environmental Triggers

While genetics play a role, environmental factors often act as triggers, initiating or worsening psoriasis flare-ups. Common triggers include:

• Stress: High levels of stress can exacerbate psoriasis symptoms.
• Infections: Streptococcal infections (e.g., strep throat) can trigger guttate psoriasis, a form of psoriasis characterized by small, droplike lesions.
• Skin Injury: Physical trauma to the skin, such as cuts, scrapes, sunburns, or even vigorous scratching, can lead to new psoriatic lesions in that area. This phenomenon is known as the Koebner phenomenon.
• Certain Medications: Beta-blockers, lithium, antimalarial drugs, and NSAIDs (nonsteroidal anti-inflammatory drugs) can sometimes trigger or worsen psoriasis.
• Alcohol and Smoking: Both alcohol consumption and smoking can contribute to psoriasis flare-ups and may reduce the effectiveness of treatments.
• Weather: Cold, dry weather can worsen symptoms, while warm, sunny weather often improves them. However, excessive sun exposure can also be a trigger.

Types of Scalp Psoriasis

While psoriasis can present in various forms, several types are commonly observed on the scalp:

• Plaque Psoriasis: The most common type, characterized by raised, red patches covered with silvery scales. On the scalp, these plaques can be thick and extensive.
• Guttate Psoriasis: Appears as small, drop-like, red spots. While more common on the torso and limbs, it can affect the scalp, often triggered by a bacterial infection.
• Inverse Psoriasis: Typically appears in skin folds (armpits, groin), but can occur behind the ears or along the hairline, presenting as smooth, red, inflamed patches without the typical scaling due to moisture in these areas.
• Pustular Psoriasis: Characterized by pus-filled bumps. This is a rarer and more severe form that can affect patches of the scalp.
• Erythrodermic Psoriasis: A very rare and severe form that causes widespread redness and shedding of skin over large areas of the body, including the scalp. It can be life-threatening and requires immediate medical attention.

Managing Scalp Psoriasis

Managing scalp psoriasis often involves a multi-pronged approach, combining topical treatments, light therapy, and systemic medications, depending on the severity.

Topical Treatments

• Corticosteroids: These anti-inflammatory medications reduce redness, itching, and scaling. They are available in various strengths and formulations (solutions, gels, foams, creams, ointments). Prolonged use of potent corticosteroids on the scalp can potentially thin the skin or lead to other side effects.
• Calcipotriene (Vitamin D Analogues): These help slow down the growth of skin cells. They are often used in combination with topical corticosteroids.
• Coal Tar: Available in shampoos, creams, and lotions, coal tar works by slowing skin cell growth and reducing inflammation, itching, and scaling. Concentration typically ranges from 0.5% to 5% in over-the-counter products.
• Salicylic Acid: This keratolytic agent helps loosen and remove scales, making other topical medications more effective. It is often found in shampoos and scalp treatments at concentrations around 2-10%.
• Tazarotene (Retinoid): A vitamin A derivative that normalizes cell growth and reduces inflammation. It is available as a gel or foam.

Light Therapy (Phototherapy)

Controlled exposure to ultraviolet (UV) light can slow down the production of skin cells. For scalp psoriasis, specialized UV combs or excimer lasers can target affected areas.

• UVB Phototherapy: Both broadband and narrowband UVB are used. Narrowband UVB is generally more effective and has fewer side effects.
• Psoralen + UVA (PUVA): Psoralen, a light-sensitizing medication, is taken orally or applied topically, followed by exposure to UVA light. PUVA is typically reserved for severe cases due to potential side effects.

Systemic Medications

For moderate to severe scalp psoriasis, medications taken orally or by injection may be necessary. These include:

• Methotrexate: An immunosuppressant that slows the rapid growth of skin cells.
• Cyclosporine: Another immunosuppressant, often used for severe cases, but typically for a limited time due to kidney side effects.
• Biologics: These newer medications target specific parts of the immune system involved in psoriasis. Examples include adalimumab, etanercept, infliximab, ustekinumab, and secukinumab.
• Oral Retinoids (e.g., Acitretin): Derived from vitamin A, these help control skin cell growth.

Hair Care Considerations

Stylists can play an important role in identifying signs of scalp psoriasis and recommending gentle hair care practices. It is crucial to avoid harsh chemical treatments (perms, relaxers, strong dyes) during flare-ups, as these can irritate the scalp and worsen symptoms. Recommend regular, gentle washing with specialized shampoos and conditioners. Advise against vigorous scratching or picking at scales, which can exacerbate the condition and potentially lead to infection or temporary hair loss.

Scalp Psoriasis vs. Seborrheic Dermatitis

It is important to differentiate scalp psoriasis from other common scalp conditions, particularly seborrheic dermatitis, as their appearances can sometimes be similar. While both can cause flaking and itching, there are key distinctions:

Feature	Scalp Psoriasis	Seborrheic Dermatitis
Appearance of Scales	Silvery-white, thick, dry, well-defined	Yellowish, greasy, oily, finer, less defined
Color of Patches	Red, inflamed	Red, often with a yellowish tint
Location	Primarily scalp (can extend beyond hairline), elbows, knees, lower back	Scalp, eyebrows, sides of nose, ears, chest
Itching	Often intense and persistent	Can be itchy, but often less severe than psoriasis
Underlying Cause	Autoimmune disorder	Overgrowth of Malassezia yeast on the skin (fungal element)

A definitive diagnosis is made by a dermatologist, who can also rule out other conditions like ringworm (tinea capitis).

Conclusion

Psoriasis of the scalp is a chronic condition requiring ongoing management. While there is no cure, various treatments can effectively control symptoms, reduce flare-ups, and improve quality of life. Understanding the condition, identifying triggers, and adhering to a treatment plan are essential for effective long-term management.