Makindo Medical Notes

Related Subjects: |Nikolsky's sign |Koebner phenomenon |Psoriatic Arthritis |Psoriasis

About

• Common, chronic relapsing/remitting skin disease
• Well demarcated erythematous plaques with silvery scales
• See the topic on Psoriatic arthropathy
• Normally a skin cell matures in 21 to 28 days but in psoriasis, this is 7 days
• Onset age usually 10-30 years

Aetiology

• Males = Females
• Immunology T cell mediated. No known infective element
• Increased keratinocyte and vascular proliferation
• Can be a family history and maybe a genetic susceptibility
• Environmental triggers

Types

• Chronic plaque psoriasis
• Guttate - rain drop like lesions often post streptococcal infection in young
• Seborrhoeic : nasolabial and retroauricular
• Flexural: body flexures
• Erythrodermic: general redness

Clinical

• Red, scaly patches, papules, and plaques
• Waxy white scales which flake off
• Usually found over extensor surfaces e.g knees and elbows and lower back
• Also under breasts and flexural - e.g. axilla
• Scales brought on by trauma - Koebner Phenomena
• Pustules: develops small sterile pustules which can be localised or generalised
• Thick well-demarcated scalp plaques
• Nail changes, including pitting and ridging are common
• Palmar plantar small deep-seated pustules form that usually only affect the palms and soles.
• Erythrodermic psoriasis: very rare needs admission if severe

Psoriatic plaque over extensor surface of elbow

Psoriatic plaque psoriasis on lower back

Differentials

• Pityriasis rosea vs Guttate
• Scalp psoriasis vs Dandruff

Investigations

• None - skin biopsy in difficult cases

Management

• Referral to a consultant dermatologist if diagnostic uncertainty, extensive disease, occupational disability or excessive time lost from work or school, involvement of the face, palms or genitalia (difficult to treat), failure of appropriate topical treatment after two or three months use, adverse reactions to topical treatment, severe or recalcitrant disease.
• Referral to rheumatology if signs of joint disease e.g. swelling and dactylitis

Topic treatment

• Simple emollients: first line used generously. Regular emollient may reduce fall of scales and help with other symptoms, including itch/ Use 3-4 times per day. Includes creams, shampoos, bath preparations
• Salicylic acid paste can be applied with coal tar or dithranol and reduces scaling
• Vitamin D analogues: A good quality Cochrane review found that topical vitamin D analogues (calcipotriol, tacalcitol and calcitriol) are more effective than placebo and more effective than coal tar
• Patients should be offered follow-up appointment within six weeks of initiating or changing topical therapy to assess treatment efficacy and acceptability. To improve adherence, the number of treatments per day should be kept to a minimum. [SIGN 122]
• Psychological issues, self-help groups and support. Exclude drug causes which can exacerbate the condition such as Beta-blockers, NSAID, Lithium
• Topical corticosteroids: (including combination preparations)
• Coal tar preparations: anti-inflammatory and reduces scaling. May be applied and then covered with emollients and bandages. More applied for thicker plaques. Has a classical smell which some find distasteful. A 1% coal tar solution lotion proved moderately more effective than a 5% coal tar solution lotion in one randomised study
• Dithranol: can be applied to large plaques. A good quality Cochrane review found that dithranol and tazarotene are more effective than placebo
• Topical retinoids: e.g. tazarotene used for mild to moderate plaque psoriasis
• Phototherapy: For widespread guttate psoriasis consider early referral for consideration of phototherapy in those who do not respond to topical therapy.

Specific therapies

• Scalp psoriasis: Short term intermittent use of potent topical corticosteroids or a combination of a potent corticosteroid and a vitamin D analogue is recommended in scalp psoriasis. (SIGN Guideline 121)
• Flexural psoriasis: Moderate potency topical corticosteroid is recommended for short term use in facial and flexural psoriasis. If moderate potency topical corticosteroids are ineffective in facial and flexural psoriasis, then vitamin D analogues or tacrolimus ointment are recommended for intermittent use. (SIGN Guideline 121)

Systemic treatment

• Systemic steroids: Unwell patients with widespread pustular psoriasis.
• Erythrodermic psoriasis: A rare, serious condition that may require systemic therapy and supportive management
• Phototherapy, immunosuppression
• Oral retinoids. Acitretin.
• Mycophenolate mofetil, Ciclosporin
• Infliximab, Etanercept, Efalizumab

Revisions

• SIGN Guideline 121: Diagnosis and management of psoriasis and psoriatic arthritis in adults