Psoriasis

Psoriasis, a chronic autoimmune inflammatory skin condition, often presents with varying symptoms. In Black patients, it’s crucial for family medicine physicians to take a thorough history, as the presentation of psoriasis can differ from that seen in other racial or ethnic groups.

• Symptom Onset: Patients will commonly report the gradual appearance of red, raised, scaly patches on the skin. Psoriasis can be localized or widespread, commonly affecting areas like the elbows, knees, scalp, and lower back.

• Itching (Pruritus): Most psoriasis patients experience itching, although pruritus may be less pronounced in Black patients compared to other groups. Itching can be a significant indicator of flare-ups.

• Family History: A family history of psoriasis or other autoimmune disorders (e.g., rheumatoid arthritis) can increase a patient's risk of developing psoriasis, as it is often genetically predisposed (HLA-Cw6 gene association).

• Comorbidities: Psoriasis in Black patients may be associated with comorbidities like metabolic syndrome, hypertension, diabetes, and cardiovascular disease. These conditions can worsen psoriasis and complicate treatment.

• Triggers: Common triggers for psoriasis flare-ups include stress, infections (especially streptococcal infections), and medications such as beta-blockers or lithium.

• Previous Treatments: Inquire about past treatment efforts, including topical corticosteroids and over-the-counter psoriasis treatments, as this helps inform future management strategies.

When examining Black patients with psoriasis, it's important to note that the clinical appearance may differ due to skin pigmentation. Psoriasis typically presents with the following signs:

• Plaque Psoriasis: This common type presents as well-defined, erythematous (red) plaques covered with silvery-white scales. However, in darker skin tones, erythema may be less obvious, with the plaques appearing darker brown or violaceous.

• Scalp Involvement: Psoriasis of the scalp can be more difficult to distinguish from seborrheic dermatitis in Black patients, presenting as dandruff-like flaking or thicker, scaly plaques.

• Inverse Psoriasis: Found in areas like the groin, underarms, and beneath the breasts, inverse psoriasis appears as smooth, shiny, red patches without significant scaling.

• Nail Psoriasis: Psoriasis may also affect the nails, causing pitting, discoloration, or onycholysis (nail separation).

• Guttate Psoriasis: Characterized by small, drop-shaped lesions, often triggered by infections like strep throat.

• Flexural Psoriasis: This form typically affects areas of skin folds (e.g., underarms, groin, beneath the breasts) and appears as shiny, erythematous patches without scales.

The treatment of psoriasis in Black patients requires a tailored approach, focusing on symptom management, prevention of flare-ups, and addressing associated comorbidities. There is no cure for psoriasis, but with effective treatment, the condition can often be well-managed. Here’s a breakdown of the main treatment options:

1. Topical Treatments

• Topical Corticosteroids: First-line treatment for localized psoriasis. Potency ranges from low to very high (e.g., clobetasol propionate 0.05%, betamethasone dipropionate 0.05%). The duration of treatment depends on the site and severity of involvement, but typically, a few weeks of daily application is recommended. Long-term use of high-potency steroids should be avoided to minimize side effects like skin thinning.

  • Dosage: Apply a thin layer to affected areas once or twice daily. Reduce frequency as symptoms improve.

  • Duration: Short-term use for flare-ups (2-4 weeks). Long-term management may require periodic breaks to prevent side effects.

• Topical Vitamin D Analogues: Calcipotriene (Dovonex) is often used in combination with steroids for mild to moderate psoriasis. It works by inhibiting skin cell proliferation.

  • Dosage: Apply to the affected areas once or twice daily.

  • Duration: Can be used for longer periods (up to several months) if well tolerated, with steroid sparing effects.

• Topical Coal Tar: Although less commonly used due to its smell and staining potential, it can be effective in reducing symptoms and scaling, especially in scalp psoriasis.

  • Dosage: Apply to affected areas as directed, usually at bedtime.

  • Duration: Can be used for long-term management.

2. Systemic Treatments

• Methotrexate: A traditional systemic immunosuppressive agent. Methotrexate inhibits the proliferation of skin cells and reduces inflammation.

  • Dosage: Typically started at 7.5 to 15 mg once weekly, with adjustments based on response and side effects. Doses can increase up to 25 mg per week.

  • Duration: Methotrexate is often used long-term but requires regular monitoring for liver toxicity and blood counts.

• Cyclosporine: A potent immunosuppressant that can be used for severe psoriasis.

  • Dosage: Initial dose of 2.5 mg/kg per day, divided into two doses, which may be adjusted based on response.

  • Duration: Short-term use (3-6 months) to control flare-ups due to potential kidney toxicity with long-term use.

• Biologic Agents (TNF-alpha inhibitors, IL-17, IL-23 inhibitors): Biologics are often reserved for moderate to severe psoriasis, especially when topical and systemic therapies fail. These agents target specific components of the immune system involved in psoriasis inflammation.

  • Etanercept (Enbrel): A TNF-alpha inhibitor that helps to reduce inflammation.

    • Dosage: 50 mg twice weekly for 3 months, followed by once weekly.

    • Duration: Long-term therapy may be needed for continuous disease control.

  • Ustekinumab (Stelara): An IL-12 and IL-23 inhibitor.

    • Dosage: Initially 45 mg (or 90 mg for patients weighing >100 kg), administered subcutaneously at weeks 0 and 4, then every 12 weeks.

    • Duration: Long-term therapy, with infrequent dosing (every 3 months).

  • Secukinumab (Cosentyx): An IL-17A inhibitor.

    • Dosage: 300 mg subcutaneously at weeks 0, 1, 2, 3, and 4, followed by once monthly.

    • Duration: Long-term, with quarterly administration after initial dosing.

3. Phototherapy

• UVB Therapy: Narrowband UVB phototherapy is an effective treatment for generalized psoriasis. The treatment involves exposing the skin to ultraviolet light to slow down the excessive skin cell production.

  • Dosage: Typically, 2-3 sessions per week, with gradual increase in UV exposure.

  • Duration: Typically, a series of 20-30 treatments is required, depending on response.

4. Lifestyle Modifications and Support

• Dietary Changes: Encourage weight management, a balanced diet, and possible supplementation with vitamin D, omega-3 fatty acids, or probiotics, as these have been suggested to improve psoriasis outcomes.

• Smoking Cessation: Smoking is a well-known trigger for psoriasis flare-ups and is associated with more severe disease. Counseling and support for smoking cessation should be provided.

• Stress Management: Since stress is a common trigger, recommending relaxation techniques, cognitive behavioral therapy, or mindfulness may improve the patient's quality of life and reduce flare-ups.