PITYRIASIS RUBRA PILARIS (PRP). Etiology The etiology is unknown A familial form of the disease...
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Transcript of PITYRIASIS RUBRA PILARIS (PRP). Etiology The etiology is unknown A familial form of the disease...
PITYRIASIS RUBRA PILARIS
(PRP)
Etiology
• The etiology is unknown• A familial form of the disease exists, with
an autosomal dominant inheritance pattern; however, most cases are sporadic
• One hypothesis is that pityriasis RPR may be related to an abnormal immune response to an antigenic trigger
• Case reports have described PRP occurring after streptococcal infections
• The incidence has been reported to be 1 case in 3500-5000 patients presenting to dermatologic clinics
• PRP occurs equally among men and women
• The familial form typically begins in early childhood
• The acquired form has peaks in the first and fifth decades of life, but it can begin at any age
Clinically• The familial form of PRP has a gradual
onset, whereas the acquired form has an acute onset
• The disease
typically spreads in
a craniocaudal
(from head to body)
direction
• PRP is characterized by orange-red or salmon-colored scaly plaques with sharp borders, which may expand to involve the entire body
• A characteristic feature is presence
of islands of unaffected skin within
the plaques
• The plaques are formed of follicular hyperkeratotic papules
• Palmoplantar keratoderma occurs in most patients and tends to have an orange hue
• Painful fissures may develop in patients with palmoplantar keratoderma
• Nail changes include distal yellow-brown discoloration, subungual hyperkeratosis, longitudinal ridging, nail plate thickening, and splinter hemorrhages
• Mucous membranes: Patients may complain of pain and irritation in the mouth. Mucous membrane changes include a diffuse whitish appearance of the
buccal mucosa, lacy whitish plaques, grayish-white papules and plaques, erythema, or possible erosions
• Pruritus, although not a major symptom, may occur in the early stages of the disease
Griffiths classificationTypeC/PDistrib.Course
I-Classic adult (>50 of cases)
As mentioned before
Gene-ralized
Often resolves within an
average of 3 y
II-Atypical adult (5% of cases)
Follicular hyper-keratosis and ichthyosiform lesions on the legs, sparse
scalp hair
Gene-ralized
Long duration (> 20 y)
TypeC/PDistrib.Course
III-Classic juvenile (10 of cases)
Similar to type I but appears in
year 1 or 2 of life
General-ized
Often resolves within an
average of 1-2 y
TypeC/PDistrib.Course
IV- Circu-mscribed juvenile
(25% of cases)
Prepubertal children; well-
demarcated scaly, erythematous plaques on the
elbows and knees, resembling
localized psoriasis
Locali-zed
Some cases
clear in the late teens
TypeC/PDistrib.Course
V- Atypical juvenile
(5% of cases)
Begins in first few years, accounts for most familial cases;
follicular hyperkeratosis, scleroderma-like
appearance of the hands and feet
Gener-alized
Chronic course
Histopathology
• Folliculat Plugging:
The follicles are filled with dense, horny (keratinous)plugs
• There are foci
of parakeratosis
in the perifo-
llicular shoulder
and in the epi-
dermis between
the follicles• At other sites, a basket-weave hyper-keratosis overlies
a prominent granular layer and there is little parakeratosis
•Although the epidermis is acanthotic, it is not, as in psoriasis, thinned above the dermal papillae, and there is no tendency for polymorphs to invade the epidermis
•There is a dermal
infiltrate of
lymphocytes
and histiocytes
Treatment• Currently, oral retinoids are the first line of
therapy. Isotretinoin has been reported to be of value, although a comprehensive review suggests that acitretin (0.5 to 0.75 mg/kg per day) may be more effective in clearing lesions. Accordingly, most patients are treated first with acitretin today
• Therapy with methotrexate(10 to 25 mg weekly, intramuscularly or orally, in divided doses, once a week) has shown variable rates of success
• Some cases respond well to photochemotherapy, some may flare, and others require combination treatment with retinoids or methotrexate
• Several cases of adult-type PRP showed significant clearance in 2 to 4 weeks with cyclosporine(5 mg/kg/day) Although most studies show lack of efficacy
• Some patients are helped by azathioprine (100 to 150 mg/day) , but this effect is also inconsistent