Psoriasis is a papulosquamous disease i.e. papules or plaques covered with scales. It is a skin and joint disease. It affects about 1-2% of general population. An uncommon variety of Psoriasis known as Pustular and erythrodermic psoriasis which occurs due to the withdrawal of systemic corticosteroids may be life-threatening to the patient.
Causes
The exact cause of psoriasis is unknown but it is widely believed to be an autoimmune disease. As it occurs in members of the same family which suggest it has a genetic predisposition. Various causes of psoriasis is mentioned below:
- Mechanical, Chemical or radiation trauma can initiate of worsening psoriasis.
- Drug (Chloroquine, lithium, beta-blockers and NSAIDs)
- Withdrawal of systemic corticosteroids can precipitate erythrodermic or generalised pustular psoriasis.
- Summer improves and winter worsens it.
Details
Age and Sex
Psoriasis could occur in a person of any sex or age but most commonly it occurs in young or middle-aged adults and in males.
Lesions
Lesions in Psoriasis is barely elevated reddish coloured papule with whitish scale but sometimes scale is visible only after stroking or scratching the surface. These papules enlarge or coalesce to form plaques. Fully established psoriasis has round reddish plaques covered with thick silvery scales. If scales are removed it leads to pinpoint bleeding on area which is known as Auspitz sign. In unstable psoriasis lesions can be induced by mechanical or other types of trauma, which is known as Koebner Phenomenon.This is commonly seen as linear arrangement of pruritic papules within scratch marks. Papules may combine and form linear plaques.
Distribution
Classical type of psoriasis involves elbows, knees, extensor aspect of limbs, scalp, and sacral region in a symmetric pattern. Palms and soles are commonly involved.
- Scalp psoriasis: Occurring in the scalp and without any symptoms but may also extend beyond scalp margins.
- Palmoplantar psoriasis: These are symmetric and affect palms and soles. If not treated it could lead to painful fissures on the lesions and may affect day to day activities of the patient.
- Nail Psoriasis: nails are involved only after nail beds are involved. It causes multiple pits on nails and accumulation of soft keratin (Nail material) under the nail plate. These are common manifestations of nail Psoriasis.
Variations
These are variants of Psoriasis which differs from classical Psoriasis presentation.
- Guttate psoriasis: Guttate means drop like. This variant is common in children and has the best prognosis. In this Guttate papules topped with white scales appear all over body especially on the trunk and it resolves within 1-2 months.
- Sebopsoriasis: Lesions have yellowish scales in this variant.
- Erythrodermic Psoriasis: Affects almost all parts of the body.
- Flexural Psoriasis (Inverse Psoriasis): Occurs in axilla and groin region.
- Pustular Psoriasis: In this variant there are pustules on top of the red (erythematous) lesions. It could be either localised (on a specific area) or generalised(All over the body). generalised pustular psoriasis is a life-threatening condition with a patient having the fever and in bad condition.
Psoriatic Arthritis
About 15% of patients with psoriasis develop arthritis at some point in their life. It may involve distal interphalangeal joints (joints between bones of hand fingers) and more commonly a few large joints. It may also mimic rheumatoid arthritis.
Complications
Complications of psoriasis are eminently those of erythroderma. Arthritis leads to disability. the patient may suffer from depression and withdraw from social activities. The incidence of alcohol abuse, obesity, diabetes and ischemic heart diseases are common among patients with psoriasis compared to general population.
Treatment
Psoriasis is an incurable disease i.e. medicines cannot turn remove disease out of patients completely, but it can be brought under control and it usually heals with pronged remissions (Remission = A temporary diminution of the severity of disease).
Following interventions if done by the patients can help in halting progression of the disease:
- Weight loss
- Avoidance of trauma or irritating agents including strong soaps and detergents
- Reducing or total withdrawal of alcohol intake
- Sunlight and sea bathing
Unstable psoriasis may be brought under control with liberal applications of topical bland emollients and supportive therapy.
Local Therapy
- Emollients: White soft paraffin and liquid paraffin soothe the skin, trap moisture, restore barrier function and help in removal of thick scales by softening them. They also potentiate the action of sunlight and UV light by improving their penetration.
- Keratolytics and Humectants: Salicylic acid and Urea help in the resolution of stable plaques.
- Corticosteroids: They are 1st preferred drugs used in stable and thick plaques. Within 2-4 weeks potent steroids are replaced with safer variants to prevent atrophy of surrounding skin.
- Coal Tar: Used for stable but resistant plaques with or without UV-B ray exposure.
- Dithranol: Its an alternative drug.
- Calcipotriol: It is effective in inducing remissions of localised plaques.
Systemic therapy
Generalized psoriasis needs systemic therapy along with local.
- Methotrexate
- PUVA Therapy
- UV-B Phototherapy
- Systemic corticosteroids (only used in life-threatening situations)
- Retinoids like Acitretin (for recalcitrant widespread psoriasis)
- Cyclosporine (used in erythrodermic and resistant psoriasis)
