SMALL AND LARGE PLAQUE PARAPSORIASIS

Introduction:

Chronic idiopathic dermatosis.

Epidemiology:

Common in middle age and elderly.
Peak during fifth decade of life.
Male predominance

Pathogenesis:

Unknown.
Both disorders characterized by superficial cutaneous lymphoid infiltrates of CD4 T cells.
Some cases of large plaque are manifestation of patch stage of MF, there is 10 to 35 % progression of large plague to more overt forms of lymphoma.

Clinical Features:

Symptoms:

Generally asymptomatic or mildly pruritic.

Location:

Trunk, extremities.(favor sun protected sites)

Signs:

Despite word plaque lesions consist of patches.
They may wax and wane early in the disease but typically become persistent and slowly progress over years.

Small Plaque Para-psoriasis:

Round Oval patches less than 5 cm in diameter.
Variably erythematous but less intense than psoriasis.
Covered with a fine scale.
Those with a yellow stain have been termed Xantho-Erythrodermia perstans.

Variant: Digitate dermatosis
Presents as elongated finger like patches symmetrically distributed on flanks.
Are exception to 5 cm rule as may be as long as 10 cm or more along their long axis.
Very low risk of progression to MF.

Large Plaque Para-psoriasis.

Presents as variable erythematous round and irregular shaped scaly patches that are larger that 5 cm.
May or may not exhibit clinical triad of atrophy, telangiectasia and hyper/hypopigmentation.(Piokiloderma vasculare atrophicans)

Variants: Retiform para-psoriasis AKA para psoriasis variegata or para-psoriasis lichenoides.

There are widespread ill-defined patches in a net like or zebra-stripe pattern.
Virtually all of these Retiform pattern progress to overt MF.

Pathology:

Small  Plaque Para-psoriasis

Mild non specific spongiotic dermatitis and parakeratosis.

Large Plaque Para-psoriasis

Interface lymphocytic infiltrate with a variable degree of lichenoid features
Some case contain atypical lymphoid cells and are indistinguishable from patch stage of MF.

Treatment:

Small Plaque Para-psoriasis:

Reassure patients that risk of development of MF is none.
May be followed with out treatment.
Treatment options include

First Line

Topical Steroids
Topical Coal Tar
Bexarotene
Protopic
Imiquimod.

2nd line:

Photo-therapy

Large Plaque Para Psoriasis

All patients should be treated.
First and second line treatment same as above.
Patients who meet the histopathological criteria of MF should be treated as such.

DARIER DISEASE

Introduction:

Autosomal dominant disease with complete penetrance and variable expressivity.
Named after French Dermatologist Jean Darier.

Epidemiology

Men and women equally affected

Pathogenesis

Clinical Features

Onset

Disease begins between age of six and 20 years

Symptoms

Moderate itching with malodor.

Aggravating Factors

Worse in summers: sweating ,heat, occlusion appear to have a role.
Lithium can provoke skin lesions in darier's disease.

Signs

Skin

Keratotic,crusted,red to brown papules that usually develop in seborrheic distribution.
Lesions can become confluent.
Small hypomelanotic macules may be admixed with keratotic papules.

Dorsal aspect of hands and feet.

In 50% patients flat topped, skin colored or brown papules occur at these sites.

Lesions in Axillae, groin and sub mammary region

Occur in most patients
Usually have mild involvement at these sites
(occasionally prominent involvement at these sites can occur and may result in misdiagnosis of HHD)

Palmo-Planter involvement:

Keratotic, keratin filled depression(pits) may be found

Oral Involvement.

Occurs in 15 to 50 % patients.
Painless white papules can occur.
Palate is the most common sites followed by gingiva, buccal mucosa and tongue.


Nail Changes:

Longitudinal red and white lines.
Longitudinal ridging and fissuring.
Wedge shaped subungual hyperkeratosis
Brittle nails that break distally forming V-shaped notches.

Clinical Subtypes

Acral Hemorrhagic type:

Red to blue-black irregular shaped, sharply demarcated macules can occur on palms, soles and dorsal aspect of hands.
Represents hemorrhage in to acantholytic vesicles.

Segmental types:

Two types:
Both have distribution of lesions along blaschkos lines.

Type 1

Linear streaks.
Age of onset, severity,and histological findings similar to generalized disease.

Types 2

Generalized disease has linear streaks with increased severity.

Complications:

Infection:

Increased frequency of skin infection due to disruption of epidermal barrier.
Patients prone to infections with bacteria, yeast, dermatophytes, HPV and  herpes simplex virus. Suspect HSV infection if sudden onset of vesicular and crusted lesions( hgic) +/- fever and malaise.
Treat with anti virals if HSV infection suspected.

Salivary glands

Oral salivary gland obstruction can occur due to duct obstruction.

Neuropsychiatric disorders

Various conditions like epilepsy,intellectual impairment,mood disorders(depression,bipolar) have been reported.

Others

Ocular complication like corneal ulceration's, Staphylococcal endophthalmitis.
SCC arising in cutaneous or mucosal sites.
Bone cysts, renal agenesis and autoimmune thyroiditis in some patients.

Pathology

Two prominent features.

Acantholysis:

Due to loss of cell adhesion's in suprabasilar cleft. This corresponds to loss of desmosomes and detachment of keratin filaments from desmosomes.

Dyskeratosis:

Due to apoptosis of keratinocytes.
Two types of dyskeratotic cells are observed.
a) Corps ronds: acantholytic enlarged keratinocytes in the malpighian layer with dark staining and partially fragmented nuclei surrounded by a clear cytoplasm and encircled by bright ring of collapsed keratin bundles.
b) Grains: small, oval cells in stratum corneum characterized by  eosinophilic cytoplasm containing shrunken parakeratotic nuclear remnants.Grains are likely derived from corps ronds.

Mild to moderate perivascular infiltrate in superficial dermis.
Overlying epidermis is acantholytic and dyskeratotic foci is thickened and shows papillomatosis and hyperkeratosis.


Differential Diagnosis:

Acrokeratosis of Hopf:

Autosomal Dominant
Described by Hopf
Presents with flat topped wart like papules on dorsal aspect of extremities.(similar to Darier disease)
Separated from Darier disease on the basis of histology: as it lacks acantholysis and dyskeratosis.

Seborrheic Dermatitis.
Grovers Disease.
HHD.

Treatment

Patient education.
Cotton clothing.
Sunscreens especially in summers.
Soap substitute.
Emollients particularly with urea or lactic acid.
Antiseptics like triclosan or betadine


First Line.

Topical Steroids
Topical Retinoids: Adapalene, tazarotene or tretinoin.
Other agents like Protopic, Pimecrolimus or Topical 5FU.

Second Line:

Oral Retinoids:

Acitretin and Isotretinoin.

May be more effective if combined with topical retinoids.
Effective in about 90 % of patients.
Oral retinoids do not induce prolonged remission in Darier disease and long-term treatment is needed to prevent relapse.
Reduce hyperkeratosis, flatten papules and may control odor.

Acitretin:
Dose 10 to 25 mg initially but can be increased gradually to 0.5 mg/kg. Can take 2 to 3 months for maximal effects.

Isotretinoin:
Starting dose at 0.5 to 1 mg per Kg.

Retinoids are teratogenic.Women should avoid pregnancy for three years after discontinuing acitretin and for one month after discontinuation of isotretinoin. Isotretinoin is thus preferred to acitretin for women of childbearing age who have severe Darier disease.


Oral steroids or Cyclosporin 

Reduce inflammation in patients with ‘eczematized’ disease, but papules and erosion's persist


Oral Contraceptives may reduce premenstrual flares.

For patients with localized hypertrophic lesions that do not respond to oral retinoids, surgical excision, laser ablation, or photodynamic therapy are therapeutic options.

Prognosis

Patients with Darier disease have a normal life expectancy, although their quality of life may be significantly impaired. The disease follows a chronic course and relapse is common when treatment is stopped.

Patient Information Leaflet
http://www.bad.org.uk/site/807/default.aspx

LICHEN NITIDUS

Introduction:

Is chronic eruption consisting of multiple tiny discrete skin coloured papuples that are arranged in clusters.Progression from lichen nitidus to lichen planus has been reported. Few authours believe it may be a clincal manifestation of crohn's disease, however it is generally accepted that lichen nitidus is not associated with any systemic disease or abnormal laboratory findings.

Exhibits Koebner phenomenon.


Clinical Features:

Symptoms

Pruritis can occur but it is an uncommon feature.

Signs

Numerous, tiny, discrete,shiny skin colured uniform, pinhead-sized papules that occasionally exhibit central depression.
Lesions can coalesce to form plaques that can have psoriasiform appearance esp on elbows and knees
Papules can be hypopigmented in dark skin individuals,however occaionslly can be hyperpimented.

Location

Flexor aspect of upper extremities,genetalis,
chest,abdomen and dorsum of hands.
oral lesions are rare.
Nail involvement in about 10 % of patients.(same findings as LP)

Pathology

Infiltrate of lymphocytes, epitheloid cells and occaionally langhans giant cells is typically clutched by the surrounding hyperplastic rete ridges in a "ball and claw" pattern.
Lichenoid infiltrate closely apposes the epidermis.

Treatment

Treatment is mainly symtomatic.

First Line

Topical steriods
Anti histamines
Topical Calcineurim inhibitors

Second Line

Same as LP

Prognosis

Two thirds of patients resolve within a year.

LICHEN STRIATUS

Introduction:

A linear asymtomatic dermatosis of unknown etiology that generally affets children.It is distributed along the Blaschkos lines.  It is more common in spring and summer and is manifestation of mosaicism.

Epidemiology:

Seen mostly in children (Age range between 4 months and 15 years.
Majorrity cases occur in preschool children.
Female to Male ratio is 2:1

Pathogenesis:

Unknown.
? abnormal immune response associated with atopy.

Clinical Features:

History:

Eruptions usually appear suddenly, develop fully over days to weeks.



Lichen Striatus

Symptoms:

Usually none but intense pruruitis occasionally

Signs:

Continous or interuppted bands of discrete or clustered papules.
Usually on extermity along blasko lines.
Can be pink or skin coloured or hypopigmented(Tan)
Ocassionally there is bilateral or multiple parallel bands.
It is uncommon for lichen striatus to involve trunk or head and neck region.
Can resolve spontaneously after years leaving postinflammatory hypopigmentation.

Nail Involvement:

onchoysis
splitting
fraying
Total loss of nails may occur


Pathology:

Lichenoid tissue reaction
varying degree of involvement of sweat glands and hair follicules.

Treatment:

Usually not needed
Topical Steriods+/- occlusion.
Topical Calcineurin inhibitors.