Our Observations

 
All of our patients, six Japanese males (mean age at the time of diagnosis 30 years) and 19 females (mean age at the time of diagnosis 26 years), sixteen of those women being Japanese, one Turkish, one Italian, and one German, told of a pruritic eruption that occurred on the trunk in the absence of a prodrome. The lesions were situated on the back (Figures 5A–I) and the neck (Figures 6A–D) mostly. In some patients the distribution of lesions on the back was wedge-shaped, seeming to cut a swath through the length of the center of the back, the apex of the wedge being caudal. In other patients lesions spared the upper part of the back and formed the negative image of a wedge on the lower part of the back. The chest was affected in 14 patients (Figures 7A–H), whereas the clavicular region (Figures 8A–C) and the abdomen was caught up in the process in but a few patients. In two patients, the upper extremities where involved. Large zones of sparing are an expected finding in prurigo pigmentosa. In most of the patients (21/25), the eruption recurred, 13 of them attesting to several recurrences over months, and 8 telling of many recurrences over years. The interval between episodes in these patients was as short as two weeks and as long as three years. The number of anatomic sites involved in the process increased, albeit slowly, in 9 patients. As but one example, the Turkish women had no lesions on the face for 10 years, but after that period of time she developed lesions on the forehead.
 
Photographs of lesions of prurigo pigmentosa on the back (Figs. 5A–I), neck (Figs.6A–D), chest (Figs. 7A–H), and clavicular region (Figs. 8A–C) as they presented themselves in our patients are presented in the following figures in a sweep from extensive to paltry involvement.

View Figure  		Fig. 5A  Prurigo pigmentosa on the back: Red urticarial papules, many of which have become confluent to form plaques.

View Figure  		Fig. 5B  Prurigo pigmentosa on the back: Erythematous urticarial papules and plaques on the back, especially the upper part of it. Note also pigmented macules.

View Figure  		Fig. 5C  Prurigo pigmentosa on the back: Erythematous papules and plaques in company with crusts. Scales as well as pigmented macules are present mostly on the lower part of the back. The upper part of the back is largely spared.

View Figure  		Fig. 5D  Prurigo pigmentosa on the back: Red papules have become confluent to form plaques in a netlike pattern and in asymmetrical fashion.

View Figure  		Fig. 5E  Prurigo pigmentosa on the back: Netlike pigmentation in the lumbar region represents the postinflammatory stage of prurigo pigmentosa.

View Figure  		Fig. 5F  Prurigo pigmentosa on the back: Many red papules and tiny vesicles are discrete, but others have become confluent, the latter resulting in formation of an incipient reticular pattern.

View Figure  		Fig. 5G  Prurigo pigmentosa on the back: The midline of the mid portion of the back is affected by red papules and pigmented macules arranged in a netlike pattern and distributed in patchy fashion.

View Figure  		Fig. 5H  Prurigo pigmentosa on the back: Reticular pigmentation in a wedge shape on the back, a consequence of resolution of urticarial papules. Some red papules have appeared newly.

View Figure  		Fig. 5I  Prurigo pigmentosa on the back: Most of the red papules and pigmented macules on the back are discrete, but some have become confluent.

View Figure  		Fig. 6A  Prurigo pigmentosa on the neck. Red papules and pigmented macules have become confluent to create a netlike pattern (picture kindly provided by Dr. Teraki, Tokyo).

View Figure  		Fig. 6B  Prurigo pigmentosa on the neck. Some red papules are discrete, whereas others have become confluent to form plaques and lesions that are linear and arcuate.

View Figure  		Fig. 6C   Prurigo pigmentosa on the neck. Discrete red papules and ill defined plaques characterized by a jaggered outline.

View Figure  		Fig. 6D  Prurigo pigmentosa on the neck. Discrete red papules and papules have joined to form an arc.

View Figure  		Fig. 7A  Prurigo pigmentosa on the chest. Red papules and pigmented macules arranged in netlike fashion (picture kindly provided by Dr. Teraki, Tokyo).

View Figure  		Fig. 7B   Prurigo pigmentosa on the chest. Discrete red papules and confluence of them to form a reticular pattern.

View Figure  		Fig. 7C  Prurigo pigmentosa on the chest. Many red papules have become confluent, of a reticular pattern being the result. The pigmented macules are the residuum of red papules that involuted.

View Figure  		Fig. 7D  Prurigo pigmentosa on the chest. Pink macules, some of which have become confluent to assume a netlike outline

View Figure  		Fig. 7E   Prurigo pigmentosa on the chest. Some bright red papules are discrete, whereas others have become confluent to form plaques with figurate shapes, chief among those being arciform. Crusts atop some papules.

View Figure  		Fig. 7F  Prurigo pigmentosa on the chest. Some orange-red papules are discrete and others have become confluent to form a plaque whose border is scalloped.

View Figure  		Fig. 6G  Prurigo pigmentosa on the chest. Slightly violaceous papules, some of them discrete and others having become confluent to assume arciform and pyramidal shapes.

View Figure  		Fig. 7H  Prurigo pigmentosa on the chest. Most of the papules pictured here are discrete, but some have become confluent. The erosions are secondary to excoriation.

View Figure  		Fig. 8A  Prurigo pigmentosa of the clavicular region. Papules and papulovesicles, most of which have become confluent to form plaques, are covered by crusts that, in large part, resulted from excoriation.

View Figure  		Fig. 8B  Prurigo pigmentosa of the clavicular region. Confluence of orange papules has resulted in hints of a reticular pattern and in ill defined plaques.

View Figure  		Fig. 8C  Prurigo pigmentosa of the clavicular region. Only a few dull pink papules are discrete, most of them having become confluent to create a somewhat netlike pattern at a site immediately above the clavicle.
 
In each of the patients, individual papules were extremely pruritic and, at the outset, hivelike. Some papules assumed an arcuate or linear shape. The papules tended to cluster and became confluent, thereby causing a netlike pattern to come into being (Figures 9 A–E). Occasionally, a blotchy pattern could be observed. In the course of the disease in 7 patients, tiny vesicles and/or pustules appeared amidst the papules. In the process of resolution, lesions flatten. As lesions subside, they sport crust and scale, but when they no longer are active, they become pigmented macules whose surface is smooth. As a result of confluence of papules, the pattern of pigmentation in prurigo pigmentosa was reticular consistently; when new papules developed between pigmented macules and more recent lesions eventually resolved, new foci of pigmentation appeared and a netlike pattern emerged. The more numerous the recurrences, the more striking is the reticular pattern of pigmentation. As a result of recurrences, different stages in the "life" of lesions of prurigo pigmentosa may be present concurrently. The clinical picture in most of the patients is complicated by signs of rubbing and scratching.
 
The following photographs (Figs. 9 A–E) show the pattern of lesions in prurigo pigmentosa.

View Figure  		Fig. 9A  Prurigo pigmentosa, pattern of lesions. Netlike pattern formed by confluence of red papules, some of which are crusted consequent to excoriation.

View Figure  		Fig. 9B  Prurigo pigmentosa, pattern of lesions. A reticular pattern has developed from linkage of pigmented macules that represent the residuum of papules that involuted

View Figure  		Fig. 9C  Prurigo pigmentosa, pattern of lesions. Incipient reticular pattern as a consequence of confluence of red papules and papulovesicles just beginning.

View Figure  		Fig. 9D  Prurigo pigmentosa, pattern of lesions. Blotchy and reticular pattern formed by confluence of rust-colored papules and smooth-surfaced and scaly pigmented macules.

View Figure  		Fig. 9E  Prurigo pigmentosa, pattern of lesions. Plaques in blotchy pattern as a consequence of confluence of them.
 
The chronological sequence of the eruption as it presented itself on the back of three of our patients is pictured in Figures 10–12. Close up views of lesions from different patients are presented in chronological order in Figures 13 A–F.

View Figure  		Fig. 10A  Prurigo pigmentosa in a young Turkish woman. Very early stage manifested as an eruption of urticarial papules distributed symmetrically and in a wedge shape on the back.

View Figure  		Fig. 10B  Prurigo pigmentosa in a young Turkish woman. Later stage as evidenced by resolution of papules, some of them covered by crust. The reticular pattern is a consequence of resolution of urticarial papules. Note also newly developed red papules on the upper part of the back and on the shoulders.

View Figure  		Fig. 10C  Prurigo pigmentosa in a young Turkish woman. End stage of the process with pigmented macules in reticular pattern being distributed in wedge.

View Figure  		Fig. 10D  Prurigo pigmentosa in a young Turkish woman. An eruption, only a few days old, developed at the same site that papules have resolved as pigmented macules.

View Figure  		Fig. 10E  Prurigo pigmentosa in a young Turkish woman. More than a year later, yet another eruption of urticarial papules appeared. A reticular pattern has begun to come into being in the lumbosacral region.

View Figure  		Fig. 10F  Prurigo pigmentosa in a young Turkish woman. Still another recurrence of papules situated amidst pigmented macules that bear testimony to papules having once been present at those very sites.double space

View Figure  		Fig. 11A  Prurigo pigmentosa in a young Japanese woman. Eruption of red papules in the vicinity of pigmented macules that represent the residuum of a previous eruption. Most of the papules are arranged in a wedge.

View Figure  		Fig. 11B  Prurigo pigmentosa in a young Japanese woman. Pigmented macules are all that remain of what once was an eruption of urticarial papules.

View Figure  		Fig. 12A  Prurigo pigmentosa in a young Japanese man. Eruption of reddish papules and vesicles in a distribution that is the negative image of a wedge.

View Figure  		Fig. 12B  Prurigo pigmentosa in a young Japanese man. After less than two weeks, papules and vesicles have resolved as pigmented macules.

View Figure  		Fig. 13A  Individual lesions of prurigo pigmentosa in chronological sequence. Pink macules, urticarial papules, and urticarial plaques.

View Figure  		Fig. 13B  Individual lesions of prurigo pigmentosa in chronological sequence. Urticarial papules and plaques, one of the papules having been excoriated.

View Figure  		Fig. 13C  Individual lesions of prurigo pigmentosa in chronological sequence. Urticarial papules and plaques, vesicles, and erosions.

View Figure  		Fig. 13D  Individual lesions of prurigo pigmentosa in chronological sequence. Urticarial papules and plaques, papulovesicles, and vesicles.

View Figure  		Fig. 13E  Individual lesions of prurigo pigmentosa in chronological sequence. Papulovesicles, vesicles, crusts, and scales. Note the reticular pattern.

View Figure  		Fig. 13F  Individual lesions of prurigo pigmentosa in chronological sequence. Crusted and scaly papules in company with pigmented macules.

View Figure  		Fig. 13G  Individual lesions of prurigo pigmentosa in chronological sequence. Pigmented macules and patches covered by scales. The reticular pattern is preserved.

View Figure  		Fig. 13H  Individual lesions of prurigo pigmentosa in chronological sequence. Smooth-surfaced pigmented macules and patches in a vaguely reticular pattern.