An update on pityriasis rosea and other similar childhood exanthems

An update on pityriasis rosea and other similar
childhood exanthems
John C. Browning
Pediatrics and Dermatology, University of Texas Health
Science Center at San Antonio, San Antonio, Texas,
Correspondence to John C. Browning, MD, FAAP,
Assistant Professor, Pediatrics and Dermatology,
University of Texas Health Science Center at San
Antonio, 7703 Floyd Curl Drive, MSC 7808, San
Antonio, TX 78229, USA
Tel: +1 210 562 5344;
e-mail: [email protected]
Current Opinion in Pediatrics 2009, 21:481–485
Purpose of review
Pityriasis rosea is a common skin condition seen in children and adults. Whereas
pityriasis rosea is a benign condition, it is important to distinguish it from other childhood
Recent findings
Pityriasis rosea can present in a variety of manners. Most often a herald patch precedes
the generalized eruption, although this is not always the case. Pityriasis rosea may lead
to undesirable outcomes when affecting pregnant women. Guttate psoriasis, secondary
syphilis, cutaneous lupus erythematosus, capillaritis, pityriasis versicolor, nummular
eczema, and cutaneous T-cell lymphoma are important to consider in the differential
diagnosis of pityriasis rosea.
Pityriasis rosea is self-limiting, usually lasting 1–3 months. Treatment may be
considered in certain cases, although there is a paucity of medical studies supporting
any definitive treatment. However, treatment may be warranted for other conditions that
mimic pityriasis rosea.
childhood exanthems, erythromycin, pityriasis rosea, syphilis
Curr Opin Pediatr 21:481–485
ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
Pityriasis rosea is a common rash seen in children and
adults. It was first described in 1798 by British physician
Robert Willan (1757–1812) under the name roseola
annulata [1]. In 1860, the French doctor Camille Melchior Gilbert named the exanthema pityriasis rosea [2].
Since then we have done much to describe the rash of
pityriasis rosea but much still remains to be discovered
regarding its cause and treatment.
Pityriasis rosea derives its name from pityriasis, meaning
bran-like, and rosea, meaning pink. In other words,
pityriasis rosea is an intelligent-sounding way of saying
pink, scaly rash. There are other ‘pityriasis rashes’ such
as pityriasis lichenoides, pityriasis alba, pityriasis rubra
pilaris, and pityriasis versicolor. Interestingly, other than
pityriasis lichenoides, these exanthems are not part of the
same family as pityriasis rosea but simply share scaliness
as a unifying feature. It was common in the early days of
dermatology to name rashes according to their appearance rather than their underlying cause.
One study found patients most commonly affected with
pityriasis rosea to be between the ages of 10 and 35 years
[3], although it has also been reported in infants [4],
1040-8703 ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
younger children [5], and the elderly [6]. Pityriasis rosea
occurs worldwide and often occurs in the spring and fall.
There is no racial or sex predilection.
Clinical appearance
Classically, pityriasis rosea begins as an erythematous,
scaly patch on the trunk known as a herald patch. It is
called a ‘herald’ patch because it is heralding the coming
of numerous smaller macules and patches. The herald
patch is usually several centimeters in size, compared
with the typical 1-cm lesions in generalized pityriasis
rosea (Fig. 1). The herald patch is often mistaken for
tinea corporis, although a simple KOH examination can
be done to exclude this diagnosis. Occasionally certain
patients will not develop a herald patch prior to the
generalized rash, or they may not remember having a
herald patch. This may be because the herald patch is
asymptomatic and, when located on the back or flank,
may not be noticed by the patient. One study found that
only 17% of patients develop the herald patch [6].
Although this number is probably low, as it reflects
patients with atypical pityriasis rosea seen in a dermatology clinic rather than a primary care clinic, it is helpful to
remember that the presence of a herald patch by history is
not necessary in making a diagnosis of pityriasis rosea.
Days to weeks later, numerous smaller scaly patches
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482 Dermatology
Figure 1 Numerous erythematous scaly macules on the back
following the skin cleavage lines
Figure 2 African–American child with inverse pityriasis rosea
involving the peri-axillary skin
Pityriasis rosea can be mistaken for other exanthems, most
commonly pityriasis lichenoides, guttate psoriasis, secondary syphilis, cutaneous lupus, capillaritis, pityriasis versicolor, and nummular eczema. Rarely, cutaneous T-cell
lymphoma may be mistaken for pityriasis rosea. These
exanthems will be further discussed later in this article.
develop on the trunk along the lines of skin cleavage.
This has often been described as a Christmas tree pattern
because skin-cleavage lines run diagonally on the back
[7]. Because of this diagonal pattern, the lesions of
pityriasis rosea often have a spindled or football shape
to them. The individual patches have a light pink color
with slight scale. They are not bright red, as would be
seen in a drug eruption, or thick and lichenified, as would
be expected with nummular eczema.
Pityriasis rosea lasts on average 6–8 weeks, although
longer and shorter courses have been reported.
In some individuals, pityriasis rosea affects the face and
extremities more than the trunk and is referred to as
inverse pityriasis rosea (Fig. 2). Pityriasis rosea in patients
with darker skin often follows an inverse pattern and may
involve the scalp and face, leaving residual pigmentary
changes in a majority [8]. Pityriasis rosea may rarely
present as a vesicular eruption [9] or similar to erythema
multiforme. [10]. Pityriasis rosea has also been known to
involve the oral mucosa [11], although this is quite rare.
There have been reports of purpuric pityriasis rosea
[12,13] and unilateral pityriasis rosea [14]. Pityriasis rosea
is often mildly pruritic, although in some cases it may be
highly pruritic or asymptomatic [7].
The cause of pityriasis rosea is unknown but it has been
hypothesized to be due to an infectious agent because of
‘outbreaks’ of pityriasis rosea among certain groups.
There has been increasing evidence implicating HHV6 and HHV-7 as causative agents of pityriasis rosea
[15,16–18]. There are also many drugs that can cause
a pityriasis rosea-like reaction. Some of these include
bismuth, captopril, barbiturates, gold, metronidazole, and
others. Recently, adalimumab, a monoclonal antibody to
tumor necrosis alpha that is used in the treatment of
psoriasis and other inflammatory conditions, was reported
to induce pityriasis rosea [19].
A recent study has shown that pityriasis rosea during
pregnancy can be very dangerous [20]. It may foreshadow premature delivery and even fetal demise. Out of 38
pregnant women with pityriasis rosea, nine had a premature delivery and five miscarried. The greatest risk to
the fetus occurred when pityriasis rosea developed in the
first 15 weeks of gestation. In one patient in the study
who was analyzed in detail, HHV-6 DNA was detected in
plasma, skin, peripheral blood mononuclear cells, as well
as placental and embryonic tissue. This is important to
note so that pregnant women may be appropriately
referred to high-risk maternal fetal medicine specialists
if they develop pityriasis rosea. Because of difficulties in
distinguishing pityriasis rosea from secondary syphilis,
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Update on pityriasis rosea and other similar childhood exanthems Browning 483
pregnant women with pityriasis rosea should have serologic testing for syphilis [21].
Diagnosing pityriasis rosea is nearly always made by history
and physical exam alone. In certain atypical cases, a skin
biopsy performed by a dermatologist may prove useful in
differentiating pityriasis rosea from other exanthems.
Histologically, acanthosis with mild psoriasiform hyperplasia and overlying focal parakeratosis may be seen [22].
Treatment for pityriasis rosea is not necessary since the
rash eventually resolves in 1–3 months. Pityriasis rosea is a
benign disease, with the exception of potential risks during
pregnancy as discussed earlier. However, in certain cases
patients may request treatment due to pruritus or cosmetic
concerns. One of the most important parts of treatment is
to inform the patient and family of the usual 1–3-month
course of the rash, its benign and noncontagious nature,
and the fact that it is not a reason to be excluded from
school or other activities. There has been some evidence
that acyclovir may be useful [23]. However, despite its
effectiveness against herpes simplex virus, several studies
have shown acyclovir to be ineffective against HHV-6 and
HHV-7 and instead have shown ganciclovir and foscarnet
to be effective antiviral agents [24,25]. This is logical, as
HHV-7 lacks the thymidine kinase gene and acyclovir is
thymidine kinase-dependent. Interestingly, there has also
been one case report of pityriasis rosea occurring during
acyclovir therapy [26]. There are no studies investigating
the use of foscarnet or ganciclovir in treating pityriasis
rosea. In the past there has been support for erythromycin
as a treatment for pityriasis rosea [27]. It has been hypothesized that the anti-inflammatory component of erythromycin, rather than the antibiotic effect, is helpful in
reducing the inflammation in pityriasis rosea. Recently,
however, another study found erythromycin not to be
useful in pityriasis rosea [28]. A separate study did not
show any benefit in using azithromycin [29]. In response to
these studies, a letter to the editor recently commented on
unpublished data using clarithromycin in treating pityriasis rosea [30]. Specifically, the author states that 50 out of
52 patients with pityriasis rosea showed improvement
during the first week of clarithromycin therapy. The author
plans to submit the results of the study in the near future.
There has been support in using narrow-band UVB phototherapy [31,32] as well as natural sunlight. Ultraviolet light
works by suppressing the cutaneous immune system.
Topical steroids offer limited benefit but may be helpful
when pruritus is present [33]. Systemic steroids have not
been shown to be effective, and the risk of systemic
steroids precludes their use in this benign condition.
Antihistamines may be of benefit when pruritus is present.
Differential diagnosis
As mentioned earlier, other exanthems may be mistaken
for pityriasis rosea. Pityriasis lichenoides chronica (PLC)
has a similar distribution and morphology to pityriasis
rosea but does not resolve within the same time period. It
can be thought of as ‘pityriasis rosea that does not go
away’. PLC can often last for months or years before full
resolution. Unlike pityriasis rosea, PLC does not begin
with a herald patch, although it tends to primarily involve
the trunk (Fig. 3). Histologically, PLC can be differentiated from pityriasis rosea by biopsy, when needed. PLC
is characterized histologically by a superficial lymphocytic infiltrate, occasional degenerate keratinocytes, and
occasional extravasated erythrocytes [34]. Narrowband
UVB phototherapy has been shown to be useful in
treating PLC. The acute form of pityriasis lichenoides
known as pityriasis lichenoides et varioliformis acuta
(PLEVA) lasts for a shorter duration than PLC. PLEVA
is characterized by erythematous papules with overlying
crusting; it should not be confused with pityriasis rosea.
Guttate psoriasis is a form of psoriasis often seen in
children following streptococcal illness. It is characterized by round and ovoid scaly, erythematous macules on
the trunk. Guttate means ‘drop-like’ because the macules
Figure 3 Pityriasis lichenoides chronica
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484 Dermatology
have the appearance of being ‘dropped’ onto the trunk. It
can be differentiated from pityriasis rosea by history (lack
of a herald patch) and by exam, as the psoriasis macules
have thicker scale. The scale can be lifted up to reveal
underlying bleeding dermal capillaries, known as Auspitz
sign. A recent study found that treating patients with
guttate psoriasis with oral penicillin or erythromycin did
not result in significant improvement [35]. Streptococcal
infection can be a trigger that induces or unmasks an
underlying predisposition for psoriasis in certain genetically susceptible children. A study of 277 Chinese children with psoriasis found that nearly 30% had guttate
psoriasis [36]. So, although it is not the most common
form of psoriasis in children, it remains important in the
differential diagnosis of pityriasis rosea.
Secondary syphilis is characterized by scaly patches on
the trunk similar in appearance to pityriasis rosea. However, syphilis affects the palms and soles and does not
begin with a herald patch, distinguishing it from pityriasis
rosea. Secondary syphilis can be distinguished histologically by the presence of numerous plasma cells in the
skin. A rapid plasma reagin (RPR) and treponemal antibody test are also useful in difficult-to-distinguish cases.
The treponemal antibody test is important due to the
prozone phenomenon, a false-negative RPR resulting
from overwhelming antibody titers [37,38]. This is an
especially important diagnosis to consider in adolescent
patients who may be engaging in sexual activity. When
secondary syphilis is seen in young children, sexual abuse
should be highly suspected.
Cutaneous lupus may occur with or without systemic
lupus erythematosus. One subtype of cutaneous lupus –
subacute cutaneous lupus erythematosus (SCLE) – has a
similar appearance to pityriasis rosea. It is specifically
characterized by erythematous scaly plaques in a photodistribution on the face, neck, and shoulders. Anti-SS-A/
Ro and anti-SS-B/La autoantibodies have been strongly
associated with SCLE [39]. SCLE can be distinguished
from pityriasis rosea primarily because of its photodistribution. It does not tend to affect covered areas such as
the lower chest and back as would be expected with
pityriasis rosea. The two diseases can also be easily
distinguished by biopsy. Histology of SCLE shows basal
vacuolar change, epidermal atrophy, and occasional
Civatte bodies [40].
with a ‘cayenne pepper’ appearance on the extremities.
Eczematoid-like purpura of Doucas and Kapetanakis is
similar to Schamberg’s disease but has overlying scale
and pruritus. A skin biopsy can easily distinguish between
pityriasis rosea and capillaritis.
Pityriasis versicolor, or tinea versicolor as it is also called,
is caused by the yeast Malasezia furfur. It is characterized
by hypopigmented or hyperpigmented macules with fine
scale on the upper chest, back, shoulders, neck, and face.
Pityriasis versicolor is more common during the summer
months and in tropical climates, as heat and humidity
facilitate overgrowth of the yeast. Remission can be easily
obtained with treatment using topical or oral antifungal
agents, although recurrence is common. Besides its
response to treatment, pityriasis versicolor can be distinguished from pityriasis rosea by its distribution (upper
trunk, neck, and face), color (hyperpigmented or hypopigmented rather than erythematous), and the presence
of finer scale than in pityriasis rosea. The presence of
yeast in the stratum corneum can easily be demonstrated
on biopsy of pityriasis versicolor.
Nummular eczema may be mistaken for pityriasis rosea
because of the ‘coin-shaped’ or nummular lesions which
are similar in appearance to the lesions of pityriasis rosea.
Nummular eczema, however, primarily involves the
extremities, whereas classic pityriasis rosea involves
the trunk. Nummular eczema is characterized by pruritus
and should rapidly improve with topical steroids and
emollients. A biopsy will easily demonstrate spongiosis
in the epidermis in nummular eczema but not in pityriasis
Cutaneous T-cell lymphoma, or mycosis fungoides as it is
also known, initially starts off as a patch stage which can
be mistaken for pityriasis rosea. Like pityriasis rosea,
cutaneous T-cell lymphoma can be mildly pruritic and
is resistant to topical steroids. It is characterized by
numerous scaly patches on the trunk and extremities.
Biopsy may be helpful, but not always. Often multiple
biopsies are required before a diagnosis of cutaneous Tcell lymphoma is made. Cutaneous T-cell lymphoma is
far more common in adults than in children but should
still be considered in certain pediatric cases [41].
Capillaritis is an idiopathic condition in which inflammation of the capillary vessels can lead to leakage of red
blood cells into the skin. Clinically this is characterized
by nonblanching erythematous patches. There are two
subtypes in particular that can be mistaken for pityriasis
rosea: Schamberg’s disease and eczematoid-like purpura
of Doucas and Kapetanakis. Schamberg’s disease is
characterized by nonblanching erythematous patches
More studies are needed to understand pityriasis rosea
and its cause. Clinical trials are also needed to determine
the best treatment for pityriasis rosea. Any study will
need to take place over several years or from multiple
locations in order to gather enough patients with pityriasis
rosea. For now, the best course of action is enthusiastic
and repeated reassurance of the patient and family, as
well as active nonintervention.
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Update on pityriasis rosea and other similar childhood exanthems Browning 485
References and recommended reading
Papers of particular interest, published within the annual period of review, have
been highlighted as:
of special interest
of outstanding interest
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