Papulosquamous diseases

Psoriasis

Psoriasis is a noncontagious skin disorder that most commonly appears as inflamed, edematous skin lesions covered with a silvery white scale. The most common type of psoriasis is plaque psoriasis

Causes Lesions of psoriasis are caused by an increase in the turnover rate of dermal cells from the normal 23 days to 3-5 days in affected areas. Patients with psoriasis have a genetic predisposition for the disease

Causes Autoimmune function: Significant evidence is accumulating that psoriasis is an autoimmune disease. Lesions of psoriasis are associated with increased activity of T cells in underlying skin. Some of the newer drugs used to treat severe psoriasis directly modify the function of lymphocytes

History Worsening of a long-term erythematous scaly area Sudden onset of many small areas of scaly redness Recent streptococcal throat infection, viral infection, immunization, use of antimalarial drug, or trauma Family history of similar rash pain Pruritus No fever Vesicles Long-term rash with recent presentation of joint pain

Physical Plaque psoriasis is characterized by raised inflamed lesions covered with a silvery white scale. This is most common on the extensor surfaces of the knees, elbows, scalp, and trunk. Guttate psoriasis presents as small red dots of psoriasis that usually appear on the trunk, arms, and legs; It frequently appears suddenly after an upper respiratory infection (URI).

Physical Inverse psoriasis occurs on the flexural surfaces, armpit, groin, under the breast, and in the skin folds. Pustular psoriasis presents as sterile pustules appearing on the hands and feet or, at times, diffusely.

Physical Erythrodermic psoriasis presents as generalized erythema, pain, itching, and fine scaling. Scalp psoriasis affects approximately 50% of patients, presenting as erythematous raised plaques with silvery white scales on the scalp

Physical Nail psoriasis may cause pits on the nails, which may develop yellowish color and become thickened. Nails may separate from the nail bed. Psoriatic arthritis affects approximately 10% of those with skin symptoms. The arthritis is usually in the hands, feet, and, at times, in larger joints. It produces stiffness, pain, and progressive joint damage

TREATMENT Many drugs that affect the rate of production of skin cells are used in psoriasis therapy alone or in combination with light therapy, stress reduction, and climatotherapy. Adjuncts to treatment include sunshine, moisturizers, and salicylic acid as a scale-removing agent. Generally, these therapies are used for patients with less than 20% of body surface area involved, unless the lesions are physically, socially, or economically disabling.

Treatment Keratolytic agents Coal tar Topical corticosteroids Vitamin D3 analogue

Treatment Treatments for more general or advanced psoriasis include UV-A light, psoralen plus UV-A light (PUVA), retinoid eg acitretin, methotrexate (particularly for arthritis), cyclosporine.

Treatment The recognition of the central role of T cells and tumour necrosis factor (TNF)-α in the pathogenesis of psoriasis led to the development of new biologic treatments.

Treatment Currently, three biologic TNF-α inhibitors: Infliximab Etanercept Adalimumab and two T-cell agents Efalizumab Alefacept

Treatment It is recommend that these biologic agents are used as a second-line therapy for patients with moderate-to-severe psoriasis who have: 1- failed to respond to conventional nonbiologic agents,

Treatment 2- Have become intolerant to conventional systemic therapy, and/or cannot receive conventional systemic therapy because of an increased risk of developing clinically relevant drug-related toxicity.

Treatment 3- cannot receive conventional systemic therapy because of an increased risk of developing clinically relevant drug-related toxicity.

Pityriasis rosea

Pityriasis rosea (PR) is a common benign papulosquamous disease. Pityriasis denotes fine scales, and rosea translates as rose colored or pink. PR can have a number of clinical variations. Its diagnosis is important because it may resemble secondary syphilis.

The disease typically begins with a solitary macule that heralds the eruption (called the herald spot/patch), which is usually a salmon-colored macule. This initial lesion enlarges over a few days to become a patch with a collarette of fine scale just inside the well-demarcated border.

Within the next 1-2 weeks, a generalized exanthem usually appears, although it may occur from hours to months after the herald patch. This secondary phase consists of bilateral and symmetric macules with a collarette scale oriented with their long axes along cleavage lines. This phase tends to resolve over the next 6 weeks, but variability is common.

Pruritus is common, usually of mild-to- moderate severity, and it occurs in 75% of patients.

Pathophysiology PR has often been considered to be a viral exanthem. Its clinical presentation supports this concept. PR has been linked to upper respiratory infections,, the incidence may increase in the fall and the spring. A single outbreak tends to elicit lifelong immunity.

Despite these tendencies, no single virus has been proven to cause the disease

The most important part of treating patients with PR is reassurance that the rash will resolve. Generally, the disease resolves within 12 weeks

Relief of pruritus is helpful and can be accomplished by using topical steroids, oral antihistamines, topical menthol-phenol lotions, and oatmeal baths. Systemic steroids are not recommended

The prognosis for PR is excellent. Patients may return to work or school because they are not considered to be contagious.

Lichen planus

Lichen planus (LP) is a pruritic, papular eruption characterized by its violaceous color; polygonal shape; and, sometimes, fine scale. It is most commonly found on the flexor surfaces of the upper extremities, on the genitalia, and on the mucous membranes

Physical In addition to the cutaneous eruption, LP can involve the mucous membranes, the genitalia, the nails, and the scalp. The clinical presentation of LP has several forms: actinic, annular, atrophic, erosive, follicular, hypertrophic, linear, pigmented, and vesicular/bullous.

Mucous membrane involvement is common and may be found without skin involvement. Lesions are most commonly found on the tongue and the buccal mucosa; they are characterized by white or gray streaks forming a linear or reticular pattern on a violaceous background. Oral lesions are classified as reticular, plaquelike, atrophic, papular, erosive, and bullous.

Patients with a cutaneous eruption may also have follicular and perifollicular violaceous, scaly, pruritic papules on the scalp. These lesions can progress to atrophic cicatricial alopecia that can appear many weeks after the skin lesions have disappeared. Pseudopelade can be a final endpoint.

In 10% of patients, ungual findings are present. Most commonly, nail plate thinning causes longitudinal grooving and ridging. Hyperpigmentation, subungual hyperkeratosis, onycholysis, and longitudinal melanonychia can result from LP. Rarely, the matrix can be permanently destroyed with prominent pterygium formation

Variations in LP include the following: Hypertrophic LP: These extremely pruritic lesions are most often found on the extensor surfaces of the lower extremities, especially around the ankles. Hypertrophic lesions are often chronic; residual pigmentation and scarring can occur when the lesions eventually clear.

Annular LP: LP papules that are purely annular are rare. Annular lesions with an atrophic center can be found on the buccal mucosa and the male genitalia. Linear LP: Isolated linear lesions may form a zosteriform lesion, or they may develop as a Köbner effect.

Actinic LP: Subtropic or actinic LP occurs in regions, such as Africa, the Middle East, and India. This mildly pruritic eruption usually spares the nails, the scalp, the mucous membranes, and covered areas. Lesions are characterized by nummular patches with a hypopigmented zone surrounding a hyperpigmented center

Atrophic LP: Atrophic LP is characterized by a few lesions, which are often the resolution of annular or hypertrophic lesions. Erosive LP: These lesions are found on the mucosal surfaces and evolve from sites of previous LP involvement.

Vesicular and bullous LP: Most commonly, these lesions develop on the lower limbs or in the mouth from preexisting LP lesions. A rare condition, lichen planus pemphigoides, is a combination of both LP and bullous pemphigoid

Follicular LP: Lichen planopilaris is characterized by keratotic papules that may coalesce into plaques. This condition is more common in women than in men, and ungual and erosive mucosal involvement is more likely to be present. A scarring alopecia may result

Pathophysiology LP is a cell-mediated immune response of unknown origin. LP may be found with other diseases of altered immunity; these conditions include ulcerative colitis, alopecia areata, vitiligo, dermatomyositis, morphea, lichen sclerosis, and myasthenia gravis.

An association is noted between LP and hepatitis C virus infection, chronic active hepatitis, and primary biliary cirrhosis. Hepatitis should be considered in patients with widespread or unusual presentations of LP. Onset or exacerbation of LP has been linked to stressful events.

Histologic Findings The histopathologic features distinguish LP based on the presence of irregular acanthosis and colloid bodies in the epidermis with destruction of the basal layer. The upper dermis has a bandlike infiltrate of lymphocytes and histiocytes.

DIFFERENTIALS Graft Versus Host Disease Lichen Nitidus Lichen Simplex Chronicus Pityriasis Rosea Psoriasis, Guttate Psoriasis, Plaque Syphilis Tinea CorporisGraft Versus Host Disease Lichen Nitidus Lichen Simplex Chronicus Pityriasis Rosea Psoriasis, Guttate Psoriasis, Plaque Syphilis Tinea Corporis

Medical Care LP is a self-limited disease that usually resolves within 8-12 months. Mild cases can be treated with fluorinated topical steroids. More severe cases, especially those with scalp, nail, and mucous membrane involvement, may need more intensive therapy

The first-line treatments of cutaneous LP are topical steroids, particularly class I or II ointments. A second choice would be systemic steroids for symptom control and possibly more rapid resolution

Oral acitretin has been shown to be effective in published studies

Patients with widespread LP may respond to narrow-band or broadband UV-B therapy. Psoralen with UV-A (PUVA) therapy for 8 weeks has been reported to be effective.