Attributes of prurigo pigmentosa said to be typical of it clinically can be conveyed best and most compellingly by quoting directly from articles dedicated to the subject. What follows are quotations from the principle articles that appeared subsequent to the first publication by Nagashima:

". . . reddish papules, some excoriated, and marked reticulate hyperpigmented motteling." Cotterill et al., 1981, British Journal of Dermatology⁶

"The eruption subsided in 1 week or ten days, leaving residual pigmentation, but new papules broke out . . . accompanied by severe itching." Yamasaki et al., 1981, The Journal of Dermatology³¹

". . . itchy reddish papules, which evolved into marked reticulate pigmentation. . . . In the pigmented area there were some reddish raised papules. . . . coalescing to form a reticulate pattern." Miyakawa et al., 1984, Dermatologica³²

"Many reddish papules . . . were distributed as dots on the reticular pigmentation." Shimizu et al., 1985, Journal of the American Academy of Dermatology³³

"Intensly puritic eruptions . . . The rash always subsided a week later leaving a reticulate pigmentation." Harms et al., 1986, Dermatologica¹²

". . . there were erythematous scaling papules confined to the reticulate areas of pigmentation, the intervening skin being clinically normal . . . " Cox et al., 1987, British Journal of Dermatology⁸

". . . puritic rash, of sudden onset, with erythematous . . . and. . . . hyperpigmented papules . . . The lesions were 2–3 mm in diameter and a hyperpigmented reticulate pattern was observed between the papules." Schepis et al., 1996, British Journal of Dermatology¹⁶

". . . mottled erythema, reticular pigmentation, small red papules and small blisters . . . some scratch marks. . . ." Murao et al., 1996, British Journal of Dermatology³⁴

". . . multiple itchy painful, vesicular lesions erupting in a disseminated pattern" Kubota et al., 1998, European Journal of Dermatology³⁵

In articles about prurigo pigmentosa that appeared after Nagashima's two seminal reports, pictures of lesions clinically are shown in about 80 patients and, although some of those photographs are wanting in quality, almost all of them correspond well with illustrations that appeared in the articles of Nagashima (Figures 4 A–H). Descriptions of the clinical aspects, the chronological sequence of individual lesions, and the course of the disease itself are strikingly similar in all articles that have dealt with those matters about prurigo pigmentosa during the past 30 years. Among the 178 patients reported on in articles reviewed by us, detailed description of clinical features was given in 168 of them. Erythematous macules distributed either in patchy or random fashion were noted in 22 patients. In almost all patients, intensely pruritic erythematous papules, 2 to 4 millimeters in diameter, were dominant; in 58 patients those papules were thought to be urticarial. Plaques were said to be present in 68 patients and those lesions were characterized as being "wheal-like" in 11 patients. Frank vesicles were claimed to have occurred in some patients^25,35–44, but pustules^16,37 or bullae ^35,44 were noted in very few of them. Signs of excoriation were apparent in 35 patients, crusts in 32, and scales in 27. In time, the lesions resolved, leaving as residuum a reticular pattern of pigmentation. The process was typified by exacerbation and remission.

What precedes immediately (Figs. 4 A–H) are clinical photographs of prurigo pigmentosa that appeared subsequent to the publication of the seminal article of Nagashima. They show features very similar to those pictured by Nagashima and his colleagues. The neck, back, and chest are favored sites. When lesions become confluent, a reticular pattern comes into being consistently.

In only 13 articles^{1,3,12,31,39,45–52} was mention made of the duration of individual papules, namely, two days to one week. The netlike pigmentation was said to have persisted for weeks and even months. Scarring was rare and developed mostly as a consequence of the effects of excoriation. No reference was made ever to involvement of mucous membranes, hair, or nails.

The lesions of prurigo pigmentosa were distributed symmetrically (146/168), the center of the trunk being the favorite site for them. Other sites of preference were the chest (108/168) and the back (129/168), neck (66/168), lumbosacral region (62/168), abdomen (43/168) and shoulders (40/168). When involvement of the chest was specified (53/108), the anterior chest was affected most commonly (35/53), especially the intermammary region (12/35).^{15, 47,51,53–55} The lateral aspect of the chest was affected in 15 patients and the submammary region in four of them.^19,22,42,43 In some patients, the arms were involved (21/168), and the legs (5/168)^{16,18,25,31,40} and the forehead very uncommonly (6/168).^{8,17,32,56–58}

Lesions of prurigo pigmentosa tended to recur and did that in at least 112 of the 168 patients. The interval of freedom from new lesions was from weeks to months, or even years. In most instances, a patient had had the disease for months, at least, before a correct diagnosis was made clinically. In articles pertinent to the subject, a meaningful history is provided for 157 patients, 81 of them having had the disease somewhere between more than a year and up to 10 years^{1,3,4,6–12,18,20,22–25,31–33,36,45,47–52,54,55,58,60–75} before diagnosis was rendered accurately. Forty one patients recounted that the eruption had recurred for several months before precise diagnosis was accomplished. ^{1,3,4,6,21,22,31,37,39,40,43–45,50,51,53,55, 56,62,64,69–71,75,76,78–80,82–84} Only in 35 patients was the disease diagnosed correctly within days or a few weeks from the time of onset of signs and symptoms.^{15,34,35,37,38,41,42,48,51,56,62,72–74,77,83–88}

In the report of Nagashima et al.,³ 12 female and two male patients had prurigo pigmentosa, a ratio of 6:1, whereas Teraki et al. found the female:male ratio of the disease to be 4:1⁷. One hundred and twenty two females and 56 males with prurigo pigmentosa now have been reported on, a convincing indication of preponderance in females. The mean age at the time of diagnosis was 25 years, females being younger (mean: 24 years) than males (mean: 27 years) when the diagnosis was made. No family history of prurigo pigmentosa was obtained in any patient. Never has the disease been diagnosed demonstrably in either prepubescent children or the elderly.

In sum, prurigo pigmentosa presented itself most often as an eruption distributed symmetrically on the trunk, with predilection for the upper part of the back, neck, shoulders, sacrum, and abdomen. Patients often tell of having had lesions for several months prior to seeking consultation, the individual lesions being short-lived, red, urticarial papules, plaques, and papulovesicles that resolved with pigmentation in reticular arrangement. Lesions were intensly pruritic and, as a consequence, evidences of excoriation, including hemorrhogic crusts, were common. Recurrences are the rule. The disease manifested itself initially in young adults mostly. Females are affected about twice as often as males.