Dermatology Online Journal

Pityriasis rubra pilaris, type IV
Jennifer Bragg MD, Agnieszka Witkiewicz MD, Seth J Orlow MD PhD, and Julie V Schaffer MD
Dermatology Online Journal 11 (4): 14

Department of Dermatology, New York University School of Medicine

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Abstract

A 4-year-old girl presented with a 3-year history of demarcated, salmon-pink, hyperkeratotic plaques, which were symmetrically distributed on the elbows, knees, ankles, and dorsal aspects of the hands and feet. A diffuse, orange-pink palmoplantar keratoderma was also evident. Clinical and histologic findings were consistent with a diagnosis of pityriasis rubra pilaris (PRP), type IV (circumscribed juvenile). Type IV PRP develops in prepubertal children, is typically localized to the distal aspects of the extremities, and has an unpredictable course. Although ultraviolet (UV) radiation can potentially exacerbate PRP, our patient has improved with broad-band UVB phototherapy.

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A 4-year-old girl presented to the Dermatologic Associates at New York University Medical Center in May 2004 for evaluation of a skin condition previously diagnosed as an ichthyosis. The lesions first appeared at age 6 months with no preceding trauma or infection. They were initially limited to the soles but over the next few months spread to involve the hands and elbows as well as the dorsal aspects of the feet and knees. The condition was pruritic with occasional development of painful fissures and had been noted to improve with sun exposure. Application of keratolytic agents and even bland emollients resulted in a burning sensation. The patient had no known medical problems, and growth and development have been normal. There was no family history of psoriasis, ichthyosis, palmoplantar keratoderma, or other skin diseases. A biopsy confirmed the diagnosis.

Treatments to date have included class-1 topical glucocorticoids, tacrolimus 0.1 percent ointment, topical and oral vitamin A, calcipotriene 0.005 percent ointment, liquor carbonis detergens 5 percent in triamcinolone 0.1 percent ointment, urea 20 percent cream, and emollients, with minimal to no response. Broad-band ultraviolet B phototherapy was recently initiated.

Well-demarcated, salmon-pink, hyperkeratotic plaques were symmetrically distributed on the elbows, knees, shins, ankles, and dorsal aspects of the hands and feet. These lesions exhibited fine, white scale, follicular prominence, and exaggerated skin markings. The skin of the palms and soles was diffusely thickened, orange-pink, and hyperlinear, with a waxy appearance. The face, scalp, trunk, and nails were not involved.

Figure 1	Figure 2

Figure 3

Histopathology reveals psoriasiform hyperplasia, marked hypergranulosis, and orthokeratosis with focal parakeratosis.

Comment

Pityriasis rubra pilaris (PRP) has been divided into six distinct subtypes (Table 1) [1, 2]. Type IV PRP (circumscribed juvenile) presents in the prepubertal years with lesions localized to the elbows, knees, ankles, and dorsal aspects of the hands and feet. In these sites, perifollicular papules with central keratotic plugs coalesce to form demarcated, scaly, erythematous plaques. A waxy, orange-red, diffuse, palmoplantar keratoderma is also commonly observed [3]. An alternative classification categorizes juvenile PRP based on duration of disease: acute (resolves in less than 6 months), acute with prolonged course (resolves within 1 year), and chronic (persists for longer than 1 year) [4]. Nail findings in PRP include thick nail plates with a rough surface or distal crumbling, yellow-brown discoloration, and subungual debris [3]. A minority of patients report pruritus or a burning sensation [5].

The pathogenesis of PRP is unknown. Theories include a dysfunction in keratinization or vitamin A metabolism, a physical trigger such as trauma, an autoimmune phenomenon, and a superantigen-mediated process [2]. Reports of an acute exanthematous form of juvenile PRP that follows an upper respiratory infection and initially presents with features reminiscent of Kawasaki disease (e.g., widespread scarlatiniform erythema, swelling of the hands and feet, and mucous-membrane involvement) support the latter hypothesis [6].

On histologic examination, an acanthotic epidermis with broad, short rete ridges and alternating orthokeratosis and parakeratosis in both vertical and horizontal directions (checkerboard pattern) is classically observed. Dilated hair follicles with keratinous plugs and with perifollicular areas of parakeratosis may also be evident, and a superficial, perivascular infiltrate of lymphocytes and macrophages is often present in the underlying dermis [7]. Additional features that help in the differentiation of PRP from psoriasis include an increased granular layer and acantholysis in the former condition [8].

Because of the relative rarity of PRP, the ability to perform randomized, double-blind, placebo-controlled trials assessing treatment options is limited. Treatments that have been attempted include topical glucocorticoids, topical vitamin A, topical vitamin D analogs, oral glucocorticoids, oral vitamin A, systemic retinoids, methotrexate, azathioprine, cyclosporine, and ultraviolet (UV) phototherapy. In a retrospective study of 30 children with PRP, five of six patients with type-III PRP treated with daily oral isotretinoin showed 90-100 percent clearing within 6 months [9]. Of the study participants with type IV PRP, three of four had an excellent response to topical glucocorticoids, one of three responded well to a modified Goeckerman regimen (UVB phototherapy and tar), and one responded poorly to topical calcipotriene. UV light may exacerbate PRP, but there have been some reports of successful treatment with psoralen plus UVA (PUVA photochemotherapy), UVA1 phototherapy, and narrow-band UVB phototherapy [10, 11, 12]. After failing to respond to multiple therapies, our patient has shown improvement after ten UVB treatments, with decreased erythema and thickness of the hyperkeratotic plaques on the distal aspects of the extremities.

Table 1. Classification of pityriasis rubra pilaris

Clinical type	% of patients*	Age at onset	Distribution	Skin findings	Course
I (classical adult)	50	Peak in the 6th decade	Generalized, beginning on the head and neck then spreading caudally	•Red-orange plaques, confluent with islands of sparing •Perifollicular papules with keratotic plugs •Diffuse, waxy PPK	Often resolves within three years
II (atypical adult)	5	Adults of various ages	Generalized	•Areas of eczematous dermatitis •Ichthyosiform scale on the legs •PPK with lamellated scale •Alopecia	Chronic
III (classic juvenile)	10†	Peaks in the first few years of life and the late teens	Generalized	•Similar to type I (see above) •<50% have palmoplantar involvement	Often resolves within three years
IV (circumscribed juvenile)	25†	Prepubertal	Focal, favoring the elbows and knees	•Well-circumscribed, scaly, erythematous plaques •Perifollicular papules with keratotic plugs •Diffuse, waxy PPK	Variable
V (atypical juvenile)	5†	First few years of life	Generalized	•Ichthyosiform dermatitis •Perifollicular papules with keratotic plugs •Scleroderma-like appearance of the hands and feet •Accounts for most familial cases of PRP	Chronic
VI (HIV-associated)	NA	Variable	Generalized	•Similar to type I (see above) •Associated with acne conglobata, hidradinitis suppurativa, and lichen spinulosus‡	May respond to anti-retroviral therapy
*Based on a series of 98 patients with PRP seen at St. John's Hospital in London between 1952 and 1972 [1] †In two series of juvenile PRP (total n=59), types III, IV, and V accounted for 45%, 50%, and <5% of cases, respectively [4, 9] ‡Referred to as the HIV-associated follicular syndrome PPK, palmoplantar keratoderma; NA, data not available

References

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2. Miralles ES, et al. Pityriasis rubra pilaris and human immunodeficiency virus infection. Br J Dermatol 1995;133:990

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5. Gross DA, et al. Pityriasis rubra pilaris. Arch Dermatol 1969;99:710

6. Betloch I, et al. Acute juvenile pityriasis rubra pilaris: a superantigen mediated disease? Pediatr Dermatol 2001;18:411

7. Soeprono FF. Histologic criteria for the diagnosis of pityriasis rubra pilaris. Am J Dermatopathol 1986;8:277

8. Magro CM, Crowson AN. The clinical and histomorphological features of pityriasis rubra pilaris: a comparative analysis with psoriasis. J Cutan Pathol 1997;24:416

9. Allison DS, et al. Pityriasis rubra pilaris in children. J Am Acad Dermatol 2002;47:386

10. Kaskel P, et al. Bath PUVA as a treatment for pityriasis rubra pilaris provoked by ultraviolet B. Br J Dermatol 1999;140:769

11. Herbst RA, et al. Combined ultraviolet A1 radiation and acitretin therapy as a treatment option for pityriasis rubra pilaris. Br J Dermatol 2000;142:574

12. Kirby B, et al. Pityriasis rubra pilaris treated with acitretin and narrow-band ultraviolet B (Re-TL-01). Br J Dermatol 2000;142:376

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