Psoriasis Flashcards
What is psoriasis?
Psoriasis is a chronic immune mediated disease.
Inflammatory skin condition characterised by clearly defined, red and scaly plaques (thickened skin).
It is classified into several subtypes
What does psoriasis look like?
Sharply demarcated erythematous plaque with micaceous scale
What is the epidemiology of psoriasis?
3% of UK population, M=F
20-30yrs and 50-60 years
75% before 40yrs
What does psoriasis effect?
Systemic disease
- 5-30% develop psoriatic arthritis
- Psychosocial implications
- Metabolic syndrome
Why does psoriasis develop?
Polygenic predisposition + environmental triggers
How does polygenic predisposition play into the development of psoriasis?
35-90% have a family history
- Both parents: 41%
- One parent: 14%
HLA-Cw6 (Chromosome 6) -> age of onset
Psoriasis susceptibility regions PSORS1-9
What environmental triggers can cause psoriasis?
Infection
Drugs
Trauma
Sunlight
What is the pathogenesis of psoriasis?
Keratinocytes are stressed
Dermal dendritic cells are activated by cytokines such as TNF-a and IL
Dermal dendritic cells -> lymph nodes, present uncertain antigen to naive T cells
Differentiation into Th (T helper) 1, 17 and 22 -> psoriatic dermis -> plaque formation
IL and TNF-a amplify inflammatory cascade, stimulate keratinocyte proliferation
VEGF -> angiogenesis
Neutrophils in acute, active, pustular disease
Cell cycle reduced from 28 days to 3-5
What does the pathogenesis of psoriasis cause?
Psoriasis is characterized by an abnormally excessive and rapid growth of the epidermal layer of the skin.
Abnormal production of skin cells (especially during wound repair) and an overabundance of skin cells result from the sequence of pathological events in psoriasis.
Skin cells are replaced every 3–5 days in psoriasis rather than the usual 28–30 days.
Describe the histology of psoriasis
Hyperkeratosis
-Thickening of stratum corneum
Neutrophils in stratum corneum
-Munro’s microabcesses
Psoriasiform hyperplasia: Acanthosis
- Thickening of squamous cell layer
- Elongated rete ridges
Dilated dermal capillaries
T cell infiltration
What should you tackle in a psoriasis history?
- Age and nature of onset
- Distribution
- Effective treatments
- Medical history
- Family history
- Medications
- QOL
How should you examine the patients skin?
- DISTRIBUTION
- Sharply demarcated, erythematous, papulosquamous plaques
- Numerous small, widely disseminated papules and plaques
- Erythroderma (>80% BSA)
- Pustules
What should you see in someone’s nails with psoriasis?
Oncholysis
Pitting
Oil spots
What else should you check/ look out for on examination appart from skin and nails?
Scalp
Koebner phenomenon
Woronoff’s ring
What is the Koebner phenomenon?
The Koebner phenomenon or Köbner phenomenon (pronunciation), also called the “Koebner response” or the “isomorphic response”, attributed to Professor Heinrich Köbner, refers to skin lesions appearing on lines of trauma.
Occurs secondary to scratching in psoriasis
What is Woronoff’s ring?
Skin condition characterized by a blanched halo of approximately uniform width surrounding psoriatic lesions after phototherapy or topical treatments.
Woronoff’s ring is a section of paler-than-normal (hypopigmented) skin which can sometimes be found surrounding a psoriasis plaque, especially those being treated with UV light and/or coal tar.
What are the subtypes of psoriasis?
Chronic Plaque Psoriasis
Guttate psoriasis
Palmo-plantar psoriasis or pustulosis
Scalp psoriasis
Nail psoriasis
Flexural/ inverse psoriasis
What is Chronic plaque psoriasis?
Symmetric large salmon coloured plaques on areas like arms, legs and back.
Plaques have thick scale
Effects extensor surfaces
What is Guttate psoriasis?
Effects children, adolescents more
Can be triggered by viral or bacterial infections
Check ASO titre
May resolve, or may trigger chronic psoriasis in susceptible individuals
What is an ASO titre?
Antistreptolysin O (ASO) titer is a blood test to measure antibodies against streptolysin O, a substance produced by group A Streptococcus bacteria.
Can show if recent infection
What does guttate psoriasis look like?
Guttate psoriasis (also known as eruptive psoriasis) is a type of psoriasis that presents as small (0.5–1.5 cm in diameter) lesions over the upper trunk and proximal extremities
What can cause palm-plantar psoriasis or pustulosis?
Smoking
Sterile inflammatory bone lesions
How does Palmo-plantar psoriasis or pustulosis effect QoL?
Studies show that psoriasis of the palms and soles tend to have greater impact on QoL compared to more extensive psoriatic involvement not involving the palms and soles
What does palmo-plantar psoriasis look like?
Skin on the palms and soles appears thick, scaly and red with yellowish brown lesions at the edges
What is alopecia?
Hair loss
What is scalp psoriasis?
Red scaly thickened patches (plaques).
Scalp psoriasis may occur in isolation or with any other form of psoriasis.
The back of the head is a common site for psoriasis, but multiple discrete areas of the scalp or the whole scalp may be affected.
Scalp psoriasis is characterised by thick silvery-white scale over well-defined red thickened skin.
May extend slightly beyond the hairline (facial psoriasis).
Often a source of social embarrassment due to flaking of the scale and severe ‘dandruff’.
Can lead to alopecia at affected sites
What is nail psoriasis?
A translucent discolouration in the nail bed that resembles a drop of oil beneath the nail plate
What is flexural/ inverse psoriasis?
Describes psoriasis localised to the skin folds and genitals.
Lack of scale
Due to the moist nature of the skin folds the appearance of the psoriasis is slightly different. It tends not to have silvery scale, but is shiny and smooth.
There may be a crack (fissure) in the depth of the skin crease. The deep red colour and well-defined borders characteristic of psoriasis may still be obvious.
How do you tell flexural psoriasis from seborrhoeic dermatitis?
Flexural psoriasis can be difficult to tell apart from seborrhoeic dermatitis, or may co-exist. Seborrhoeic dermatitis in skin folds tends to present as thin salmon-pink patches that are less well defined than psoriasis. If there is any doubt which is responsible, or there is thought to be overlap of the two conditions, the term sebopsoriasis may be used
What can trigger flexure/ inverse psoriasis?
Can be triggered by localised dermatophyte, candidate or bacterial infection
What is pustular psoriasis?
Generalised red tender patches with sterile yellow pustules
Acute onset
May feel unwell
What can cause pustular psoriasis?
Pregnancy
Rapid taper/ stop steroids
Hypocalcaemia
Infection
What is erythrodermic psoriasis?
Psoriatic erythroderma (also known as erythrodermic psoriasis) represents a generalized form of psoriasis that affects all body sites, including the face, hands, feet, nails, trunk, and extremities
“Red men” syndrome
> 80% body surface area covered
How do you diagnose psoriasis?
Clinical accumen
SKin biopsy if atypical
What are some of the differential diagnosis?
Seborrhoeic dermatitis
Lichen planus
Mycosis fungoides
Bowens disease, drug eruption, infection, secondary syphillis, contact dermatitis, extramammary Pagets etc etc
How can GPs treat psoriasis?
How do dermatology treat psoriasis?
Dermatology referral…
Crude coal tar (inpatient or day treatment)
Dithranol: since 1916 (can burn)
UVB phototherapy (not same as subbed) -Guttate
How do you treat the systemic problem of psoriasis?
Retinoid - Acitretin
-Teratogenic, LFTs, lipids
Immunosuppression
- Methotrexate
- –Can treat PsArthritis
- –Max improvement
- Ciclosporin
- –Renal, cancer risk
Biologic Therapies
- Injectable
- Qualifying criteria
- High cost
- Anti-TNF: Etanercept, infliximab, adalimimab
- IL-12,23: Ustekinumab
- Patient can form antibodies to biologic
how do you treat Erythrodermic Psoriasis?
Admit
FLUID BALANCE
Bloods/ IV access
Thick greasy ointment emollients
?Systemic or biologic treatment
?Trigger
How do you monitor a patients progress?
Psoriases Area Severity Index (PASI)
-Surface area, plaque colour, thickness, scale
Dermatology Life Quality Index (DLQI)
-QOL in last 1 week
How does psoriasis effect mortality?
Men with severe psoriasis died 3.5 years earlier than controls.
Women with severe psoriasis died 4.4 years earlier than controls
What conditions is psoriasis associated with?
Associated with:
- Cardiovascular disease,
- Smoking,
- Alcohol,
- The metabolic syndrome
- Depression
- Suicide
- Potentially harmful drug and light therapies
- Possibly melanoma and non-melanoma skin cancers
