Psoriasis - definition, epidemiology, pathogenesis, classification, diagnosis and differential
diagnosis.
Topical and systemic treatment of psoriasis.
- Psoriasis – autoimmune, chronic-recurrent dermatosis characterized by T-cell
mediated inflammatory reaction & subsequent epidermal hyperproliferation
▪ Epidemiology:
▪ Affects 1-3% in EU, 1:1 ratio
▪ Pathogenesis:
▪ Genetics:
◦ Type I psoriasis - <40yo, family history & HLA-Cw6, HLA-B13, HLA-B57, HLA-DR7
association
◦ Type II psoriasis - >40yo, sporadic, no HLA association
▪ Sequence of events is unclear. Probably keratinocytes with ⬆ cytokine production
cause ⬆ epidermal proliferation, neutrophils migration & vessels proliferation.
▪ Triggers: streptococcal infections, viral infection (shingles, rubella, measles)
medications (ACE inhibitors, β-blockers, Lithium, antimalarials, gold, IFN), alcohol,
stress, skin injury, metabolic syndrome & obesity
▪ Köebner phenomenon – minor skin injury can lead to psoriasis development in lesion
“isomorphic response”. OBS occurs also in lichen planus, vitiligo, Molluscum…
▪ Classification:
▪ Psoriasis vulgaris
◦ Chronic stable, plaque-type psoriasis
◦ Guttate psoriasis
◦ Inverse psoriasis
▪ Psoriatic erythroderma
▪ Pustular psoriasis
◦ Palmoplantar pustular psoriasis “Barver-Königsbeck”
◦ Acrodermatitis continua suppurativa “Hallopeau”
◦ Generalized pustular psoriasis “von Zumbusch”
◦ Annular pustular psoriasis
◦ Impetigo herpetiformis “pustular psoriasis in pregnancy”
▪ Drug-induced prosriasis
▪ Psoriatic nail disease
▪ Psoriatic arthritis
▪ Clinical manifestations:
▪ Sites of predilection: scalp, retroauricular area, knees, elbows, sacrum, nails
▪ Morphology: sharply bordered erythematous patches & plaques with silvery scale
, ▪ Psoriasis vulgaris
▪ Chronic stable, plaque-type psoriasis – small papules evolve into plaques. Silvery
scale (⬆ typical). In knees, elbows, sacrum, scalp, retroauricular area. If untreated,
plaques remain for months-years
▪ Guttate psoriasis – exanthem ∼ 2-3weeks. Macules & papules evolve into plaques
with silvery scale. In trunk (& extremities, face). In children or young adults, usually
after strep pharyngitis.
▪ Intertriginous psoriasis – macerated & fissured (no plaques or silvery scale). In axilla
& groin. Diff diagnosis: candida, intertrigo
▪ Inverse psoriasis – overlaps with intertriginous (almost same). In flexural areas;
axilla, groin, breasts (except knees & elbows)
▪ Psoriatic erythroderma – in entire skin. Can suddenly develop from Guttate or long-
standing psoriasis after aggressive therapy. OBS when confronted with possible PE, think
about Pityriasis rubra pilaris.
diagnosis.
Topical and systemic treatment of psoriasis.
- Psoriasis – autoimmune, chronic-recurrent dermatosis characterized by T-cell
mediated inflammatory reaction & subsequent epidermal hyperproliferation
▪ Epidemiology:
▪ Affects 1-3% in EU, 1:1 ratio
▪ Pathogenesis:
▪ Genetics:
◦ Type I psoriasis - <40yo, family history & HLA-Cw6, HLA-B13, HLA-B57, HLA-DR7
association
◦ Type II psoriasis - >40yo, sporadic, no HLA association
▪ Sequence of events is unclear. Probably keratinocytes with ⬆ cytokine production
cause ⬆ epidermal proliferation, neutrophils migration & vessels proliferation.
▪ Triggers: streptococcal infections, viral infection (shingles, rubella, measles)
medications (ACE inhibitors, β-blockers, Lithium, antimalarials, gold, IFN), alcohol,
stress, skin injury, metabolic syndrome & obesity
▪ Köebner phenomenon – minor skin injury can lead to psoriasis development in lesion
“isomorphic response”. OBS occurs also in lichen planus, vitiligo, Molluscum…
▪ Classification:
▪ Psoriasis vulgaris
◦ Chronic stable, plaque-type psoriasis
◦ Guttate psoriasis
◦ Inverse psoriasis
▪ Psoriatic erythroderma
▪ Pustular psoriasis
◦ Palmoplantar pustular psoriasis “Barver-Königsbeck”
◦ Acrodermatitis continua suppurativa “Hallopeau”
◦ Generalized pustular psoriasis “von Zumbusch”
◦ Annular pustular psoriasis
◦ Impetigo herpetiformis “pustular psoriasis in pregnancy”
▪ Drug-induced prosriasis
▪ Psoriatic nail disease
▪ Psoriatic arthritis
▪ Clinical manifestations:
▪ Sites of predilection: scalp, retroauricular area, knees, elbows, sacrum, nails
▪ Morphology: sharply bordered erythematous patches & plaques with silvery scale
, ▪ Psoriasis vulgaris
▪ Chronic stable, plaque-type psoriasis – small papules evolve into plaques. Silvery
scale (⬆ typical). In knees, elbows, sacrum, scalp, retroauricular area. If untreated,
plaques remain for months-years
▪ Guttate psoriasis – exanthem ∼ 2-3weeks. Macules & papules evolve into plaques
with silvery scale. In trunk (& extremities, face). In children or young adults, usually
after strep pharyngitis.
▪ Intertriginous psoriasis – macerated & fissured (no plaques or silvery scale). In axilla
& groin. Diff diagnosis: candida, intertrigo
▪ Inverse psoriasis – overlaps with intertriginous (almost same). In flexural areas;
axilla, groin, breasts (except knees & elbows)
▪ Psoriatic erythroderma – in entire skin. Can suddenly develop from Guttate or long-
standing psoriasis after aggressive therapy. OBS when confronted with possible PE, think
about Pityriasis rubra pilaris.
