Psoriasis is a common chronic inflammatory skin condition that occurs as a result of complex interactions between genetic, environmental and immunological factors. 

Onset may occur at any age but is most common between the ages of 15 and 35 years. The main sites of the body affected are the scalp, areas over the elbows and knees, the lower part of the back, and genitalia, as well as the nails.

The basal skin cells divide too quickly, and the newly formed cells become evident as profuse scales or plaques of epidermal tissue. As a result of the increased number of basal cells and rapid cell passage, the normal events of cell maturation and growth cannot occur, which prevents the normal protective layers of the skin to form. Current evidence supports an immunologic basis for psoriasis. The primary defect is unknown. Periods of emotional stress and anxiety aggravate the condition, and trauma, infections, and seasonal and hormonal changes also are trigger factors.

The plaques that are present in psoriasis arise as a result of the hyperproliferation of epidermal cells, which leads to the thickening of the skin as a result of the skin trying to replace itself too quickly. The capillaries become dilated, and the white blood cells infiltrate the cells. This stimulates the T cells to release chemokines and cytokines, which cause the keratinocyte hyperproliferation. This results in erythema, inflammation and a scaly appearance of the skin.

Types of Psoriasis, including: 

  • Chronic plaque psoriasis, which affects the head/hairline, back, abdomen, knees, and elbows 
  • Flexural (inverse) psoriasis, which affects the knees and axillae
  • Guttate psoriasis, with widespread coverage
  • Erythrodermic psoriasis, affecting 90% of the total body surface
  • Pustular psoriasis
  • Palmar-plantar psoriasis
  • Facial psoriasis
  • Scalp psoriasis

Clinical Manifestations

  • Symptoms range from a cosmetic annoyance to a physically disabling and disfiguring affliction.
  • Lesions appear as red, raised patches of skin covered with silvery scales.
  • If scales are scraped away, the dark red base of lesion is exposed, with multiple bleeding points. Patches are dry and may or may not itch. 
  • The condition may involve nail pitting, discoloration, crumbling beneath the free edges, and separation of the nail plate. 
  • In erythrodermic psoriasis, the patient is acutely ill, with fever, chills, and an electrolyte imbalance.

Assessment Findings
  • Arthritic symptoms 
  • Characteristic location of lesions: scalp, chest, elbows, knees, back, buttocks 
  • Itching 
  • Lesions (red and usually forming well-defined patches) 
  • Pain 
  • Patches, consisting of silver scales that flake off or thicken and cover the lesions
  • Pustules 
Diagnostic Findings
  • The presence of the classic plaque-type lesions generally confirms the diagnosis of psoriasis.
  • The biopsy of the skin is of little diagnostic value. 
  • Signs of nail and scalp involvement and for positive family history.
Treatments can include both topical and systemic therapies. Emollients are the most important part of a skincare regimen to hydrate the dry skin.

Medical Management

Topical corticosteroids 
Mild to moderate lesions -Aristocort, Kenalog, Valisone 
Moderate to severe lesions -Lidex, Psorcon, 
Severe lesions -Temovate, Diprolene, Ultravate 
Lesions on face and groin -Aclovate, DesOwen,

Topical nonsteroidals 
Mild to severe -Retinoids such as tazarotene (Tazorac) Vitamin D3 derivative calcipotriene (Dovonex)

Coal tar products 
Mild to moderate lesions-Coal tar and salicylic acid ointment (Aquatar, Estar gel, Fototar, Zetar); anthralin (AnthraDerm, Dritho-Cream) 

Medicated shampoos 
Scalp lesions -Neutrogena T-Gel, T-Sal, Zetar, Head & Shoulders, Desenex, Selsun Blue,(emulsifying agent with phenol, saline solution, and mineral oil) 

Intralesional therapy 
Thick plaques and nails -Kenalog, Cordran-impregnated tape, Fluoroplex

Systemic therapy 
Extensive lesions and nails -Methotrexate (Folex, Mexate); hydrourea (Hydrea)

Moderate to severe lesions UVA or UVB light with or without topical medications 
PUVA (combines UVA light with oral psoralens, or topical tripsoralen)

Teaching Patients Self-Care 
  • Advise patients that topical corticosteroid preparations on the face and around eyes predispose to cataract development.
  • Teach patient to avoid exposure to the sun when undergoing PUVA treatments. 
  • Skin must be protected with sunscreen and clothing, and sunglasses should be worn. 
  • Remind the patient to schedule ophthalmic examinations on a regular basis.
  • Advise female patients of childbearing age that PUVA therapy is teratogenic (can cause fetal defects).
  • If indicated, help to ease the emotional strain and give support. 
  • Encourage patients to join a support group.

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