Early Stage Prurigo Pigmentosa : A Case Report
Emel ONAYGİL1, Abdullah SONGUR2, Zekayi KUTLUBAY3, Cuyan DEMİRKESEN1
1Department of Pathology, İstanbul University, Cerrahpaşa Faculty of Medicine, İSTANBUL, TURKEY
2Department of Dermatology Şanlıurfa Balıklıgol Hospital, ŞANLIURFA, TURKEY
3İstanbul University, Cerrahpaşa Faculty of Medicine, İSTANBUL, TURKEY
Keywords: Prurigo Pigmentosa, Diet, Histopathology
Prurigo pigmentosa is a rare inflammatory dermatosis that primarily affects adolescents and young adults. Even though it is most commonly
seen in Japanese women, other countries have reported cases with increasing frequency. It is characterized by erythematous papules and macules
on the trunk, neck and chest that resolve leaving a reticulate hyperpigmentation. Some endogenous factors related with ketosis like fasting, diet,
diabetes, pregnancy and exogenous agents like chrome, nickel, para-amino compounds have been accused of playing a role in etiology. Here we
would like to present a case of a 16-year-old female patient who was referred to our clinic with pruritic lesions on the trunk and neck, consistent
with the initial phase of prurigo pigmentosa, after a period of strict diet. Prurigo pigmentosa is a disease with distinctive histologic and clinical
features. Due to its rare occurrence, an accurate diagnosis may be particularly challenging. Clinicopathological correlation is therefore crucial in
the diagnosis of the disease in its early phase.
Prurigo pigmentosa is a rare dermatosis characterized by
localized, recurrent, erythematous papular and macular
lesions on the back, neck, and chest that resolve to leave
hyperpigmentation. Although the etiology of the disease
is not well known, it primarily affects adolescents and
young adults in the spring and summer seasons1
would like to present a case of a 16-year-old female patient
who was referred to our clinic with pruritic lesions on the
trunk and neck, consistent with the initial phase of prurigo
pigmentosa, after a period of strict diet.
A 16-year-old female was referred to the dermatology
department of our hospital with a one-month history of
pruritic rashes on her trunk and neck. Her complaints had
started as red, pruritic vesicles that paled and regressed
within a week but recurrence of the pruritic vesicles was
observed. It was reported that one month before the eruption
of the lesions, the patient undertook a strict diet, and lost
twenty kilograms within three months. There was no drug
history related to the lesions but the patient was diagnosed
with asthma two weeks after the eruption of the lesions,
and she started being treated for asthma. Dermatological
examination revealed excoriated erythematous papules on
the neck, back, clavicular and intermammarian areas, as well as pale brown reticular hyperpigmentation on the front
chest with increasing prominence at the intermammarian
area (Figure 1
). Laboratory work was normal for complete
blood count, erythrocyte sedimentation rate, biochemistry
test, and complete urinalysis.
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|Figure 1: Edematous, papules and plaques, some of which are
excoriated, coalescing on the neck laterals, intermammarian area,
and anterior chest.
The histopathological examination of a punch biopsy
from the back of the patient revealed neutrophils in the
epidermis that were mostly widely spread, or grouped
into clusters. There was irregular acanthosis, dyskeratotic
cells, spongiosis, neutrophilic and eosinophilic spongiosis
in the epidermis. The upper dermis revealed perivascular
and interstitial infiltration of neutrophils, intermingled
with lymphocytes, histiosytes, and a small number of
eosinophils. Vascular proliferation, and neutrophils within
the lumina of some vessels were evident (Figure 2,3).
When the clinical findings, the history of the patient, and
the histopathological features were evaluated together, it
was concluded that the symptoms were consistent with
the early stage of prurigo pigmentosa. After the patient
was diagnosed as prurigo pigmentosa through clinical and
histopathological evaluations, she was treated with 100
mg/day doxycycline. Ten days later, the patient reported
complete relief from itchiness, and it was observed that the
existing papules resolved to leave brown hyperpigmentation
(Figure 4). It was decided to continue the treatment with
doxycycline for two months.
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|Figure 2: Perivascular and interstitial infiltration composed of
neutrophils, lymphocytes, and histiocytes, vascular proliferation
in the upper dermis (H&E; x40).
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|Figure 3: Neutrophils and dyskeratotic cells widely spread or
grouped in clusters within the epidermis (H&E; x100).
Click Here to Zoom
|Figure 4: On the 10th day of Doxycycline 100 mg/g treatment,
papules and plaques resolved to leave light hyperpigmentation.
Prurigo pigmentosa was first described in 1971 by
Nagashima et al. through observing the signs in 8
. In the following years, the Japanese literature documented 300 cases of prurigo pigmentosa2
it is rarely seen outside Japan, cases have been reported in
other countries with increasing frequency3,4
. Baykal et
al. published a series of case studies of 6 patients in 2006 demonstrating that the disease is not as uncommon in
Turkey as originally believed5
Studies have shown that prurigo pigmentosa lesions
are symmetrically spread on the back, chest, and neck.
In our case, the lesions were also observed in these
locations, forming a symmetrical pattern. As seen in our
case, lesions in the early stage of the disease consisted of
erythematous papules and plaque that progressed into
papules, papulovesicles, and vesicles and later resolved to
leave pigmented macules. It is possible to observe lesions in
different stages in the same area6.
Even though earlier studies claimed that histopathological
results were nonspecific, Boer and Ackerman described
different histopathological characteristics in three different
stages of the disease7. According to their description, the
early stage of the disease is characterized by a neutrophilic
infiltration around the vessels in the superficial dermis. Later,
the neutrophilic infiltration spreads to the interstitial areas in
the papillary dermis. In the following stage, the neutrophils
infiltrate the epidermis, causing spongiosis, ballooning, and
necrosis in the keratinocytes7. The biopsy taken from
the back of our patient revealed neutrophilic infiltration in
the perivascular and interstitial areas of the upper dermis,
as well as dyskeratotic cells, clusters of neutrophils, and
neutrophilic spongiosis within the epidermis, suggesting
that the lesions are in the early stage of the disease. Boer
and Ackerman stated that in fully developed lesions
of prurigo pigmentosa, lymphocytes and eosinophils
appear in the upper dermis, and lead to an infiltration in
a patchy, lichenoid pattern6. This stage is characterized
by lymphocytes, as well as spongiosis and ballooning in
the epidermis, intra- and subepidermal vesicle formation,
and an abundance of necrotic keratinocytes. Lesions in
this stage should be differentiated from acute spongiotic
dermatitis, viral exanthem, and necrolytic erythemas. The
above mentioned authors pointed out that in the later
stages of the disease, the epidermis takes a hyperplastic,
hyperkeratotic, and hyperpigmented appearance, while
the dermis is characterised by lymphocytic infiltration and
pigment-laden macrophages6. During this stage, chronic
spongiotic dermatitis and postinflammatory pigmentation
should be noted in the differential diagnosis7.
The etiology of prurigo pigmentosa is not well known but
it is believed that the disease may have been caused by
some endogenous and exogenous factors. The endogenous
factors include ketosis, diet, starvation, diabetes, pregnancy,
and Helicobacter pylori infection while exogenous factors
include sweating, clothes rubbing against skin, as well as exposure to allergens such as para-amino compounds,
trichlorophenol, chrome, and nickel8-16.
As seen in our case, it is common in women of late
adolescent age to lose weight within a short period of time
by undertaking carbohydrate-poor diets16. Because the
blood glucose level drops during starvation, a ketogenic
metabolism is initiated in the body. The ketone particles
that form as a result of this process pass from the blood into
tissues and cell cytoplasms, joining metabolic processes
within, or remaining around vessels to cause perivascular
Various studies discuss the relation between prurigo
pigmentosa and starvation, carbohydrate-poor diets due
to their high ketogenic effect, and the ketosis observed in
diabetes mellitus4,8-10. In a series of four cases that
Hijazi et al. presented in 2014, they observed that one
patient developed the lesions after dieting during the month
of Ramadan, and two patients developed lesions after a
strict diet7. However, the relation between ketosis and
the disease has not been firmly established. Further studies
need to be undertaken to understand the pathogenesis of
Prurigo pigmentosa is a rare disease with an unclear
etiopathogenesis. The histopathological results vary
according to the clinical stages of the disease. The diagnosis
may be particularly challenging due to its rare occurrence.
Clinicopathological correlation is therefore crucial when
diagnosing the disease accurately.
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