Papulosquamous diseases

Pityriasis rosea Acute and self limiting disorder of unknown etiology. Characterised by oval scaly paules and plaques mainly over the trunk.

Manifestation Firstly, a single lesion about 2-5 cm also known as “herald patch”appears. Somedays later many smaller plaques appear on the trunk,arms and thighs. Plaques are oval,pink and have delicate peripheral collarette of scale. They are distributed parallel to the ribs,radiating away from the spine. Itching is present,may be mild. The eruption fades spontaneously in 4-8 weeks. Common in teenagers and young adults.

Herald patch

Collarette scale

In atypical PR (20% of patients), the herald patch may be missing or confluent with other lesions. The distribution of the rash may be peripheral, and facial involvement may be seen in children. Involvement of the axilla and groin (inverse variant) can also be seen. TYPES of lesion: – PR gigantea – PR urticata – Vesicular – Pustular – Purpuric – Erythema multiforme–like. Oral lesions of various types have been reported with PR, including erythematous plaques, hemorrhagic puncta, and ulcers.

Extensive pityriasis rosea showing a ‘fir tree’ distribution on the back.

Pityriasis rosea Psoriasis (Guttate) Lichen planus Secondary syphilis Tinea corporis Mycosis fungoides (cutaneous T- cell lymphoma) Discoid lupus erythematosus Pityriasis lichenoides Pityriasis versicolor Nummular eczema Seborrhoeic dermatitis Drug eruptions Differential diagnosis

Treatment Self limiting disease. Treatment doesn’t hasten the clearance. Antihistamines,calamine lotion Mild topical steroid can help. PUV A UVB BANDS

Lichenoid eruption

Lichen planus (LP)

Lichen planus (LP) is a rash characterised by intensely itchy polygonal papules with violaceous hue involving the skin and less commonly the oral or genital mucosa, hair and nails and/or the scalp. The most frequent oral presentation is asymptomatic reticular LP, but painful erosive or ulcerative areas may appear.

ETIOLOGY Cause unknown but immune pathogenesis has been suggested because of finding of IGM at the dermo epidermal junction and it’s association with some autoimmune diseases like myesthenia gravis, thymoma and graft-versus-host disease

Shiny flat-topped papules of lichen planus.

Pathology Hyperkeratosis Prominent granular layer Basal cell degeneration forming apoptotic bodies Heavy T lymphocyte- sawtooth dermo-epidermal junction.

Presentation Two third of cases occurs in years age group. Male=female Tend to start at limbs. It may spread rapidly to become genelarized within 4 weeks. Localized forms are more common and progress much more slowly. Lesion are very itchy, flat topped polygonal papules,few mm in size,and the surface shows white line known as wickham’s striae. Initially the papules are red but later become voilaceous. Are also found in the mouth, particularly inside the cheeks, in about 50% of patients, and oral lesions may be the sole manifestation of the disease.

Presentation

May rapidly become generalised Lesions may last for months to years Although the skin plaques are usually itchy, patients rub rather than scratch, so that excoriations are uncommon.

The lesion are symmetrical and involves: Forearm and wrist Lower legs and thighs Genitalia Palmas and soles In two third of cases buccal mucosa is involved. In most cases papules flattens to leave a pigmentation, but some may become hypertrophied.

The thickened lesions characteristic of hypertrophic lichen planus on the shins.

LP

Lichen planus: classic white lacy network lying on the buccal mucosa.

LP as seen in tongue

As in psoriasis, the Koebner phenomenon may occur The nails are usually normal, but in about 10% of patients changes ranging from fine longitudinal grooves to destruction of the entire nail fold and bed is seen Scalp lesions can cause a patchy scarring alopecia.

Lichen planus: striking Koebner effect on the forearm.

Nail changes in LP

Drugs causing lichen planus like eruption Antibiotic:tetracycline,streptomycin Antimalairial:quinine,choloquinine Anti-tb:isoniazid,ethambutol Diuretics:furesemide,thiazide Antiarthritic:gold,penicillamine.

Variants of lichen planus. Annular Atrophic Bullous Follicular Hypertrophic Ulcerative

Course Individual lesions may last for many months and the eruption as a whole tends to last about 1 year. In the hypertrophic variant of the disease, thick warty lesions usually around the ankles, often last for many years. As lesions resolve, they become darker, flatter and leave discrete brown or grey macules. About one in six patients will have a recurrence

Complications Nail and hair loss can be permanent. The ulcerative form of lichen planus in the mouth may lead to squamous cell carcinoma. Ulceration, usually over bony prominences, may be disabling, especially if it is on the soles. Any association with liver disease is probably caused by the coexisting hepatitis infections.

Differential diagnosis Psoriasis Pityriasis rosea Discoid lupus erythematosus Tinea Nummular eczema Seborrhoeic dermatitis Secondary syphilis Drug eruptions

Investigations The diagnosis is usually obvious clinically. The histology is characteristic, so a biopsy will confirm the diagnosis if necessary.

Treatment Treatment can be difficult. If drugs are suspected as the cause, they should be stopped and substituted. Potent topical steroids will sometimes relieve symptoms and flatten the plaques. Systemic steroids work too, but are recommended only in special situations (e.g. unusually extensive involvement, nail destruction or painful and erosive oral lichen planus). Treatment with photochemotherapy with psoralen and ultraviolet A (PUVA) or with narrow-band UVB may reduce pruritus and help to clear up the skin lesions. Acitretin has also helped some patients with stubborn lichen planus. Antihistamines may blunt the itch. Mucous membrane lesions are usually asymptomatic and do not require treatment; if they do, then applications of a corticosteroid or tacrolimus in a gel base may be helpful.

Lichen sclerosis Uncommon condition. It is a chronic disese. White lichenified atrophic lesion are seen over the genitalia. Cause unknown but associated with autoimmune diseases.

Pathology Epidermis may be thickenes,thinned or hyperkeratotic. Upper dermis is oedematous, hyalinsed, and acellular. Lower dermis there is lymphocyte infiltration.

Clinical presentation. More common in female about 10 times. Common in middle age although can occur during childhood. More common in genital area but may involve trunk or arms. Individual lesion are few mm in size white and atrophic. These atrophic lesion may aggregate into wrinkled plaques.

Hyperkeratosis,telangectasia,purpura and even blistering can occur. Perineal and vulval lesion causes itching and soreness. In male due to recurrent balanitis and ulceration of glans there is chance of urethral stricture and phimosis to develop.

Complication Dysuria Recurrent balanitis Scc on long standing cases infrequently.

Management Non genital lesion (those over the mouth or trunk) requires no treatment –sponateously regresses. In female genital lesion mild to moderate steroid. Sometimes steroid along with antibacterial cream can be used. Long term follow up is necessary and biopsy of the suspected lesion has to be done.