What are the different types of psoriasis?

Types of Psoriasis

Psoriasis presents in several distinct clinical forms, with plaque psoriasis being the most common (>80% of cases), followed by inverse, guttate, pustular, erythrodermic, nail, and psoriatic arthritis variants. 1

Plaque Psoriasis (Psoriasis Vulgaris)

• Most common form affecting over 80% of patients with psoriasis, characterized by well-demarcated, red plaques with silvery scale 1, 2, 3
• Commonly involves the scalp, elbows, knees, and presacral region, though any skin area can be affected including palms, soles, nails, and genitalia 1, 2
• Plaques are typically erythematous, raised, and covered with thick silvery-white scales that may be pruritic, painful, or bleed 1
• The course varies with plaques tending to remain static or slowly enlarge; spontaneous resolution is possible but rare 4

Inverse (Flexural) Psoriasis

• Characterized by erythematous plaques with minimal scale due to the moist nature of affected areas 1
• Common locations include axillary, genital, perineal, intergluteal, and inframammary areas, as well as flexural surfaces like antecubital fossae 1, 2
• Lesions are thinner than plaque-type psoriasis with little to no scaling 4

Guttate Psoriasis

• Presents as dew-drop-like, 1-10mm salmon-pink papules with fine scale 1, 2
• Primarily affects the trunk and proximal extremities 1, 2
• Common in individuals younger than 30 years and occurs in less than 2% of psoriasis patients 1
• Frequently has sudden onset, often appearing abruptly after bacterial or viral upper respiratory infections 4

Pustular Psoriasis

• Defined by large collections of neutrophils in the stratum corneum that are clinically apparent as pustules on an erythematous background 1, 5
• Two main variants exist:
  • Generalized pustular psoriasis (von Zumbusch variant): An uncommon, severe form accompanied by fever and systemic toxicity with widespread pustules 1, 5
  • Localized pustular variant: Involves palms and soles, with or without evidence of classic plaque-type disease 1, 5
• Cutaneous lesions characteristic of psoriasis vulgaris may be present before, during, or after an acute pustular episode 1

Erythrodermic Psoriasis

• Can develop gradually from chronic plaque disease or acutely with little preceding psoriasis 1
• Presents with generalized erythema covering nearly the entire body surface area with varying degrees of scaling 1, 2
• Systemic manifestations include:
  • Altered thermoregulation leading to chills and hypothermia 1
  • Fluid loss potentially causing dehydration 1
  • Fever and malaise are common 1, 2
• Represents one of the most severe clinical variants requiring distinct treatment approach 1, 4

Nail Psoriasis (Psoriatic Onychodystrophy)

• Can occur in all psoriasis subtypes 1
• Fingernails involved in approximately 50% of all psoriatic patients and toenails in 35% 1, 2
• Characteristic changes include pitting, onycholysis, subungual hyperkeratosis, and the oil-drop sign 1, 2
• Up to 90% of patients with psoriatic arthritis may have nail changes 1
• Represents a significant therapeutic challenge 1

Psoriatic Arthritis

• An inflammatory arthropathy associated with psoriasis, classified as a member of the seronegative spondyloarthropathies 1
• Affects up to 30% of patients with psoriasis 4
• Characterized by joint swelling, tenderness, and dactylitis ("sausage digits") 1

Important Clinical Considerations

• Clinical findings in individual patients frequently overlap in more than one category, making strict phenotyping challenging 1
• Diagnosis is primarily clinical and usually does not require complementary examinations, though biopsy may be necessary in atypical presentations 2, 5
• Psoriasis severity is defined by body surface area (BSA): <3% BSA is mild, 3-10% is moderate, and ≥10% is severe 1
• Disease can be severe irrespective of BSA when it causes serious emotional consequences, occurs in selected locations (hands, feet, scalp, face, genitals), or causes intractable pruritus 1