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Dermatopathology: Practical & Conceptual

July – September 1998 | Volume 4, No. 3

Simplifying parapsoriasis

Ackerman, A. Bernard; Joshi, Rajiv S.; Resnik, Kenneth S.

Introduction

That the term parapsoriasis continues to be confusing becomes apparent from observing how it is used in some current standard textbooks of dermatology. Parapsoriasis is defined and classified in them as follows:

From Andrews' Diseases of the Skin. 8th Ed.

Arnold HL Jr, Odom RB, James WD. Andrews’ Diseases of the skin. 8th Ed. Philadelphia: WB Saunders, 1990.

Definition: “The term ‘parapsoriasis’ was applied by Brocq (1902) to a group of maculopapular scaly eruptions of slow evolution, whose marked chronicity, resistance to treatment, and absence of subjective symptoms are characteristic features. Although the eruptions are psoriasiform and lichenoid, the diseases do not correspond to psoriasis, lichen planus, or other recognized dermatoses, and although the details of the eruptions do not harmonize, there is sufficient essential conformity to justify placing them in a distinct group.”

Classification:

1. Pityriasis lichenoides chronica

2. Pityriasis lichenoides et varioliformis acuta (also known as parapsoriasis lichenoides, Habermann’s disease, Mucha-Habermann disease, and parapsoriasis varioliformis acuta)

3. Parapsoriasis en plaques (includes both small plaque and large plaque parapsoriasis)”

The authors acknowledge that 10% of lesions of large plaque parapsoriasis “may eventuate in T-cell lymphoma.”

From Clinical Dermatology. 2nd Ed.

Habif TP. Clinical Dermatology. 2nd Ed. St. Louis: CV Mosby, 1990:540-1.

No definition given. Small plaque parapsoriasis is not discussed. “There are two different presentations [of mycosis fungoides] in the patch phase: a red, scaly eczematous-like eruption; and an atrophic, mottled, telangiectatic eruption referred to as large-patch parapsoriasis or poikiloderma atrophicans vasculare.”

From Principles and Practice of Dermatology

Sams WM Jr, Lynch PJ (Eds). Principles and Practice of Dermatology. New York: Churchill Livingstone, 1990:286-7.

No definition given. “The conditions considered under the term parapsoriasis are among the most confusing in all of dermatology.”

Classification:

1. Small plaque parapsoriasis (includes atypical pityriasis rosea and digitate dermatosis)

2. Large plaque parapsoriasis (approximately 20% develop into patch stage mycosis fungoides)

3. Retiform parapsoriasis (including poikiloderma vasculare atrophicans and variegata patterns)

Both these retiform variants are otherwise clinically and histologically similar to large-plaque parapsoriasis and are likewise characterized by a transition to cutaneous T-cell lymphoma in a significant number of instances.”

From Textbook of Dermatology. 5th Ed.

Champion RH, Burton JL, Ebling FJG (Eds). Rook/Wilkinson/Ebling. Textbook of Dermatology. 5th Ed. Blackwell Scientific Publications, 1992:569,1957.

Definition of chronic superficial scaly dermatitis:

“A chronic condition characterized by the presence of round or oval erythematous, slight scaly patches on the limbs and trunk, which histologically reveal mild eczematous changes with little or no dermal infiltrate. The condition is ill-defined since the features are rather non-specific, and diagnosis should be regarded as a provisional one which may need to be modified by subsequent developments. This condition was formerly included with various pre-lymphomatous eruptions under the general term of ‘parapsoriasis.’”

Definition of pityriasis lichenoides:

“A disease of unknown aetiology having an acute form, commoner in the young – pityriasis lichenoides et varioliformis acuta (or Mucha-Habermann disease) – and a chronic form, once known as guttate parapsoriasis. There is an important but rare variant named lymphomatoid papulosis.”

No classification given. “Persistent superficial dermatitis,” “benign form of parapsoriasis-en-plaques,” and “digitate dermatosis” are considered synonyms for “chronic superficial scaly dermatitis.” “Parapsoriasis en gouttes,” “guttate parapsoriasis,” “Mucha-Habermann disease,” and “lymphomatoid papulosis” are considered synonyms for “pityriasis lichenoides.” The authors acknowledge that “It is important to realize that some cases originally diagnosed as chronic superficial scaly dermatitis may later develop reticulate pigmentation or atrophy, and these cases may then need to be reclassified as prelymphomatous poikiloderma.”

From Dermatology. 3rd Ed.

Moschella SL, Hurley HJ (Eds). Dermatology. 3rd Ed. Philadelphia: WB Saunders, 1992:638.

Definition: “The group of disorders classified under the heading of parapsoriasis are heterogenous in clinical presentation, histopathology, and course. . . . Despite the normal implications, none of the parapsoriases bears any relationship to psoriasis, except for an occasional clinical morphologic similarity.”

Classification:

1. Pityriasis lichenoides:

Acute (PLEVA, Mucha-Habermann disease)

Chronic (Juliusberg variant, PLC)

2.Small plaque parapsoriasis

Variant: Digitate dermatosis (xanthoerythroderma perstans)

3. Large plaque parapsoriasis

Variant: Retiform parapsoriasis (atrophic parapsoriasis, parakeratosis variegata [Unna])”

The authors acknowledge that large plaque parapsoriasis has “the potential for progression to malignancy” and “it could be argued that patients who develop cutaneous T-cell lymphoma have had malignant clone(s) of lymphocytes from the start.”

From Dermatology in General Medicine. 4th ed.

Fitzpatrick TB, Eisen Az, Wolff K, Freedberg IM, Austen KF (Eds). Dermatology in General Medicine. 4th Ed. New York: Mcgraw-Hill, 1993.

Definition: “Group of disorders characterized by a persistent scaling inflammatory eruption. Although originally thought to be related to psoriasis, this idea is now out of favor. Two clinicopathologic features set the parapsoriasis group apart from other purely inflammatory dermatoses: the relation to malignant lymphoproliferative lesions, and the coexistence and/or overlapping of entities in this group.”

Classification:

1. Large plaque parapsoriasis

Variants: poikilodermatous type, retiform type

“Approximately 10 to 30 percent of cases with large plaque parapsoriasis progress to mycosis fungoides.”

2. Small plaque parapsoriasis (digitate dermatosis)

3. Pityriasis lichenoides:

a. Pityriasis lichenoides et varioliformis acuta (Mucha-Habermann)

b. Pityriasis lichenoides chronica (Juliusberg)

c. Lymphomatoid papulosis”

From Cutaneous Medicine and Surgery. An Integrated Program in Dermatology.

Arndt KA, Robinson JK, Leboit PE, Wintroub BU (Eds). Cutaneous Medicine and Surgery. An Integrated Program in Dermatology. Philadelphia: WB Saunders, 1996;222-4.

Definition: “The term small plaque parapsoriasis refers to a benign, chronic persistent, asymptomatic cutaneous disease of unknown etiology characterized by the presence of ovoid, scaly, brown or yellowish macules and patches. It is also known as digitate dermatosis . . . xanthoerythrodermia perstans refers to those lesions that are identical to digitate dermatosis but of a yellow color . . . Large plaque parapsoriasis and its variants have come to be recognized as the patch stage of mycosis fungoides.”

No classification given.

Conclusions

As becomes apparent from perusal of definitions and classifications of parapsoriasis in contemporary texts of dermatology, the term parapsoriasis is applied to three different conditions, i.e., Mucha-Habermann disease, mycosis fungoides that presents itself only as flattish lesions, and lymphomatoid papulosis.

Mucha-Habermann disease is an inflammatory process that can be divided roughly, according to different appearances of lesions, as pityriasis lichenoides et varioliformis acuta and pityriasis lichenoides chronica. In the acute rapidly evolving form, the lesions are seen initially to be red macules that quickly become red or purple papules, papulovesicles, ulcers, and eschars that heal with scars. In the chronic slowly evolving form, lesions are seen to be slightly scaly pink or tan papules.

Mycosis fungoides is a systemic lymphoma that manifests itself first in the skin in a way that is so remarkably diverse that a host of confounding names has been given to each of them. For example, flat lesions can be divided into small plaque parapsoriasis and large plaque parapsoriasis. Macules of small plaque parapsoriasis usually are round (guttate parapsoriasis) and/or ellipsoid (digitate dermatosis), whereas patches of large plaque parapsoriasis are called by names such as xanthoerythroderma perstans, parapsoriasis en plaques, parakeratosis variegata, and poikiloderma vasculare atrophicans. We consider all of the aforementioned conditions to be expressions of mycosis fungoides. A universal patch, i.e., erythroderma, is termed Sezary syndrome, one or a few discrete plaques on the lower part of the leg are designated pagetoid reticulosis, and pendulous tumors near the axillae and groin are referred to as granulomatous slack skin. All of these are manifestations of mycosis fungoides. To complicate terminology further, synonyms exist for nearly all of these designations, e.g., chronic superficial scaly dermatitis for digitate dermatosis and Woringer-Kolopp disease for pagetoid reticulosis.

Lymphomatoid papulosis is a systemic lymphoma that presents itself in the skin with lesions whose appearance is distinctive. Usually there are clusters of red-brown papules, some of which are smooth or scaly, others crusted, and still others sometimes ulcerated and covered by an eschar. Uncommonly, lesions typical of lymphomatoid papulosis are present concurrently with lesions of mycosis fungoides (and even of Hodgkin’s disease). There is no relation between Mucha-Habermann disease, an inflammatory process, and lymphomatoid papulosis, a malignant neoplastic one.

In sum, Mucha-Habermann, mycosis fungoides, and lymphomatoid papulosis can be diagnosed for what they are by distinctive morphologic (gross and microscopic) findings. The term parapsoriasis not only fails to enhance recognition and understanding of them, but it hinders those efforts decidedly. For that reason, the term parapsoriasis should be abandoned in favor of specific diagnoses, namely, Mucha-Habermann disease, mycosis fungoides, and lymphomatoid papulosis. Perhaps that can be effectuated before the 100th anniversary in 2002 of the introduction of the term parapsoriasis by Brocq.

Drs. Ackerman and Resnik are at the Institute. Dr. Joshi did this work while a Visiting Fellow at the Institute. He is a lecturer of Dermatology, B.Y.L. Nair Ch. Hospital & T.N. Medical College, Mumbai 400 008, India. Reviewed by Mario DiLeonardo, M.D.