Psoriasis | Medical Science Optional Notes for UPSC PDF Download

Chronic Inflammatory Skin Condition

Psoriasis is a chronic skin condition characterized by clearly defined, red, and scaly plaques, resulting in thickened skin.

Etiology

• Prevalence:
  • Affects approximately 2-4% of both males and females.
• Lifelong Persistence:
  • Tends to persist throughout life, exhibiting fluctuations in both extent and severity.
• Aggravating Factors:
  • Aggravating factors include Streptococcal tonsillitis, injuries like cuts and abrasions, obesity, smoking, excessive alcohol consumption, and discontinuation of oral steroids or potent topical corticosteroids.
• Genetic Influence:
  • Genetic factors play a significant role, influencing the type of psoriasis an individual experiences and its response to treatment.
  • Genome-wide association studies reveal an association between HLA-Cw6 and early onset psoriasis as well as guttate psoriasis.

Psoriasis Types

• Guttate Psoriasis:
  • Characterized by multiple small erythematous, scaling papules.
  • Often follows upper respiratory tract infections with β-hemolytic streptococci.
  • Most prevalent in children and young adults.
• Plaque Type Psoriasis:
  • Features stable, slowly enlarging plaques that remain essentially unchanged for extended periods.
  • Commonly affects areas such as the elbows, knees, gluteal cleft, and scalp.
• Pustular Psoriasis:
  • Notable for fever lasting several days, a concurrent generalized eruption of sterile pustules, and intense erythema in the background.
  • Precipitated by local irritants, pregnancy, medications, infections, and systemic glucocorticoid withdrawal.
  • Oral retinoids are the preferred treatment for nonpregnant patients.
• Erythrodermic Psoriasis:
  • Involves widespread inflammation and exfoliation of the skin over a significant portion of the body surface.
  • Accompanied by severe dryness, itching, swelling, and pain.
• Inverse Psoriasis:
  • Patches often affect skin folds, particularly around the genitals, armpits, intergluteal cleft (between the buttocks), and inframammary fold (under the breasts).

Psoriasis Histopathology

• Parakeratosis without Hyperkeratosis: Presence of parakeratosis without an increase in keratinization.
• Acanthosis with Downward Elongation of Rete Ridges: Thickening of the epidermis with elongation of rete ridges.
• Suprapapillary Thinning: Thinning of the suprapapillary region.
• Munro Microabscesses: Occurrence of Munro microabscesses in the epidermis.
• Increased Mitotic Figures above Basal Layer: Elevated mitotic figures observed above the basal layer.
• Prominent Dermal Capillaries: Notable prominence of dermal capillaries.

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Clinical Features

• Psoriasis typically presents as symmetrically distributed, red, scaly plaques with well-defined edges.
• Silvery white scales are common, while plaques in skin folds may appear shiny with a moist, peeling surface.
• Common sites include the scalp, elbows, and knees, but psoriasis can affect any part of the skin.
• Persistent plaques are common without treatment, and itching, though mostly mild, can be severe in some cases.
• Fingernail involvement may manifest as punctate pitting, onycholysis, nail thickening, or subungual hyperkeratosis.
• Auspitz sign is observed, characterized by bleeding when the scale is lifted from the plaque.

Psoriasis Treatment

• General Advice:
  • Patients should be well-informed about their skin condition and treatment.
  • Beneficial practices include not smoking, avoiding excessive alcohol, and maintaining optimal weight.
• Topical Therapy:
  • Mild psoriasis is often treated with topical agents.
  • Treatment selection may depend on body site, extent, and severity of psoriasis.
  • Options include emollients, coal tar preparations, dithranol, salicylic acid, vitamin D analogues (calcipotriol), topical corticosteroids, and calcineurin inhibitors (tacrolimus, pimecrolimus).
• Phototherapy:
  • Phototherapy with ultraviolet (UV) radiation is offered at many psoriasis centers.
  • Types of phototherapy include Narrowband UVB, Broadband UVB, and Photochemotherapy (PUVA).
• Systemic Therapy:
  • Moderate to severe psoriasis may require systemic agents or phototherapy.
  • Common treatments include methotrexate, ciclosporin, acitretin, mycophenolate, and apremilast.
  • Systemic corticosteroids are best avoided due to the risk of severe withdrawal flare and adverse effects.
• Biologies:
  • Biologic agents include anti-TNFα (infliximab, adalimumab, etanercept), IL-12/23 antagonist (ustekinumab), and IL-17 antagonists (secukinumab).

Psoriatic Arthropathies

• Definition:
  • Psoriatic arthritis (PsA) is a chronic inflammatory arthritis with variable clinical presentations, often associated with skin and nail psoriasis.
• Prevalence:
  • Approximately 30% of individuals with psoriasis develop psoriatic arthritis.
  • In 60-70% of cases, psoriasis precedes joint disease.
  • In 15-20% of cases, both manifestations appear within 1 year of each other.
  • In about 15-20% of cases, arthritis precedes the onset of psoriasis, posing a diagnostic challenge.
• Presentation:
  • Five subtypes of PsA: Symmetric, Asymmetric, Distal Interphalangeal Predominant (DIP), Spondylitis, and Arthritis Mutilans.
  • Symmetric arthritis resembles rheumatoid arthritis but is generally milder.
  • Asymmetric arthritis can affect any joint and may manifest as "sausage digits."
  • DIP is the classic form, occurring in about 5% of PsA patients, involving fingers and toes.
  • Spondylitis occurs in about 5% of PsA cases.
  • Arthritis mutilans is severe and deforming, primarily affecting small joints in the hands and feet (accounts for <5% of cases).
• Nail Involvement Patterns:
  • Six identified patterns of nail involvement: Pitting, Horizontal Ridges, Onycholysis, Yellowish Discoloration of Nail Margins, Dystrophic Hyperkeratosis, and Combinations of these findings.

Diagnosis

• Inflammatory Articular Disease: A patient must exhibit inflammatory articular disease involving joints, spine, or entheseal areas.
• Scoring Criteria: Accumulation of >3 points from the following categories is required for meeting CASPAR criteria.
• Evidence of Psoriasis: Presence of current psoriasis, a personal history of psoriasis, or a family history of psoriasis.
• Psoriatic Nail Dystrophy: Typical psoriatic nail dystrophy observed during the current physical examination.
• Rheumatoid Factor: A negative test result for rheumatoid factor.
• Dactylitis: Either current dactylitis or a history of dactylitis recorded by a rheumatologist.
• Radiographic Evidence: Radiographic evidence of juxtaarticular new bone formation in the hand or foot.

Radiological features

• "Pencil-in-Cup" Deformity: Psoriatic arthropathies exhibit a distinctive "pencil-in-cup" deformity on radiographs.
• Marginal Erosions with Bony Proliferation ("Whiskering"): Radiographic images reveal marginal erosions accompanied by adjacent bony proliferation, often referred to as "whiskering."
• Small-Joint Ankylosis: Ankylosis of small joints is a characteristic radiological feature of psoriatic arthropathies.
• Osteolysis of Phalangeal and Metacarpal Bone: Radiological findings include osteolysis affecting phalangeal and metacarpal bones.
• Telescoping of Digits: Psoriatic arthropathies may present with telescoping of digits, a phenomenon observed in radiological images.

Psoriatic Arthropathies

Treatment

• Treatment objectives should focus on relieving pain and improving the patient's functionality.

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Pharmacotherapy

• Traditional approaches involve nonsteroidal anti-inflammatory drugs (NSAIDs) and local corticosteroid injections.
• Disease-modifying antirheumatic drugs (DMARDs) were traditionally reserved for cases resistant to NSAIDs.
• Early DMARD treatment is now recommended for patients with active disease, considering the potential development of erosive and deforming arthritis in 40% of cases.

DMARDs

• DMARD options include methotrexate, sulfasalazine, cyclosporine, leflunomide, and biologic agents.
• Biologic agents encompass anti-TNF-alpha medications, interleukin-12 (IL-12), IL-17, or IL-23 monoclonal antibodies.

Biological Agents

• The introduction of anti-TNF-alpha agents (etanercept, infliximab, adalimumab, and golimumab) has significantly transformed Psoriatic Arthritis (PsA) treatment.
• Ustekinumab, a monoclonal antibody targeting the shared IL-23/IL-12p40 subunit, proves effective in both psoriasis and PsA.
• Emerging drugs like anti-IL-17 pathway agents (secukinumab, brodalumab) and an oral phosphodiesterase-4 inhibitor (apremilast) show efficacy for both psoriasis and PsA.

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Physical Therapy

Rehabilitation treatment for Psoriatic Arthritis (PsA) should be personalized and initiated early in the disease progression.
The program should encompass:

• Rest: Both local and systemic rest should be considered.
• Exercise: Various forms, including passive and active exercises, stretching, strengthening, and endurance exercises.
• Modalities: Heat and cold treatments, such as warm tub soaks or applying warm compresses or cold packs, can provide temporary pain relief and reduce joint swelling.
• Orthotics: Application for upper and lower extremities, as well as spinal support.
• Assistive Devices:
• Devices for gait assistance and adaptive tools for self-care tasks. This may involve modifications to homes and automobiles.
• Education: Informing patients about the disease, energy conservation techniques, and joint protection measures.
• Vocational Adjustments: Considering possible modifications to accommodate vocational needs.

Surgical Therapy

In cases of severe pain or significant contractures, surgical intervention may be considered.
Surgical options include:

• Arthroscopic Synovectomy: Effective for severe, chronic, monoarticular synovitis.
• Arthritis Mutilans: Surgical interventions typically focus on salvaging the hand. Combinations of arthrodesis, arthroplasty, and bone grafts may be employed to lengthen digits, with the goal of maintaining the pinch mechanism of the thumb and the first two fingers.

Psoriasis-Repeats

Q1: Describe the clinical features and management of Psoriasis. (2005) 

Q2: Describe Koebner's phenomenon and enumerate various skin disorders in which it is observed. (2010)

Q3: Enumerate the classical histopathologic features of Psoriasis vulgaris and their clinical correlation. (2011) 

Q4: Enumerate types of psoriatic arthropathies. How will you manage a case of severe psoriatic arthropathies? (2010)