Skin Inflammation Treatments Quiz

Psoriasis Lecture Notes

• Psoriasis is a chronic, disfiguring, inflammatory, and proliferative skin condition.
• Skin lesions are red, scaly, and sharply demarcated plaques.
• Psoriasis commonly affects extensor surfaces and scalp.
• Genetic and environmental factors influence its development.
• Skin lesions vary in duration, with periods of flares and remissions.
• It affects 2% of the global population.
• Caucasians are most affected.
• Males and females are equally affected.

Pathogenesis

• Psoriasis is a T-cell-mediated inflammatory disease.
• Keratinocytes (skin cells) hyperproliferate (grow rapidly).
• Keratinocyte maturation is impaired.
• Inflammation and vascular changes occur.
• Genetic factors play a role, with HLA-Cw6 being a notable genetic marker.
• Skin cells regenerate every 4 days compared to 28 days in healthy people.

Clinical Features

• Psoriasis lesions are typically round or oval, well-defined, and erythematous (reddened) with plaques.
• Lesions are often symmetrical.
• Covered with white, silvery scales.
• Commonly found on extensor extremities (elbows, knees, buttocks, and scalp).

Distribution of Lesions

• Psoriasis lesions can appear on various parts of the body, including the scalp, elbows, knees, and the area around the navel (umbilicus).
• They can also appear on the ears, and nails.

Associated Diseases

• Arthritis
• Enteropathy (intestinal disease)
• Myopathy (muscle disease)
• Heart disease
• Spondylitis(spinal joint inflammation)

Histopathology

• Thickening of the epidermis.
• Retention of nuclei in keratinocytes (keratin-producing skin cells) in the stratum corneum (outermost skin layer). This causes silvery scales.
• Munro microabscesses in the stratum corneum.
• Spongiform pustules in the Malpighian layer (a deeper skin layer).
• Tortuous (winding) and dilated blood vessels are present in the dermis.

Clinical Types

• Chronic stable plaque psoriasis (psoriasis vulgaris)

  • Salmon-pink, scaly plaques.
  • Common on extensor extremities (elbows, knees, etc).
  • Koebner's phenomenon (isomorphic response to trauma). Lesions develop to the site of trauma.
  • Oil drop sign (appears on nails).
  • Auspitz's sign (pinpoint bleeding after scraping lesions).

• Guttate psoriasis:

  • Small, 0.5-1.5 cm papules and plaques.
  • Early onset, often in children, after a streptococcal throat infection.
  • Spontaneous remission is possible.

• Erythrodermic psoriasis:

  • Classic lesions are lost.
  • Entire skin becomes erythematous (red) and scaly.
  • Febrile (accompanied by fever).
  • Severe, generalized condition impacting the entire skin.

Triggering Factors for Erythrodermic Psoriasis

• Systemic infections.
• High-potency topical or oral steroid withdrawals.
• Methotrexate withdrawal.
• Phototoxicity (sun sensitivity).
• Irritant contact dermatitis.
• Medications.

Generalized pustular psoriasis

• Gradual or acute onset.
• Pustules form on erythematous skin surfaces.
• Associated with weight loss, hypocalcemia (low blood calcium), muscle weakness, leukocytosis (high white blood cell count), elevated ESR (erythrocyte sedimentation rate).
• Fever may be present.

Generalized pustular psoriasis triggering factors:

• Infections.
• Stress.
• Pregnancy.
• Lithium.
• Hypocalcemia.
• Irritant contact dermatitis.
• Corticosteroid withdrawal.

Localized Pustular Psoriasis (Palmoplantar)

• Common in women, typically in their 50s and 60s.
• Characterized by deep-seated pustules.
• Palmoplantar areas (palms and soles) are commonly affected.
• May mimic hand-foot eczema.
• Often aggravated by trauma.

Palmoplantar, nail, and scalp involvement

• Palmoplantar:

• Typical scaly patches, with silvery scales.

• Absence of vesiculation (small blisters).

• Knuckles often show thickening.

• Nail Involvement:

• 25%-50% of patients.

• Fingernails more often affected than toenails.

• Onycholysis (separation of nails from nail bed).

• Nail pitting.

• Subungual hyperkeratosis (thickening under the nail).

• "Oil drop sign"

• Scalp:

• Very thick plaques develop.

• Dry, silvery scales.

• Often extends beyond the hairline.

Treatment

• Mild: Topical corticosteroids, Vitamin D analogs.
• Moderate: Topical corticosteroids + phototherapy, vitamin D analogs.
• Severe: Topical medications + systemic agents (methotrexate, retinoids, cyclosporine), biologics.