Pityriasis rosea is a common, self-limiting skin rash characterized by oval lesions on the trunk and extremities. It is likely caused by a virus such as human herpesvirus-6 or -7. The rash begins with a single large 'herald patch' and spreads within 2-6 weeks. While usually resolving within 3 months, it causes moderate to severe itching. Treatment focuses on relieving itching with topical corticosteroids or antihistamines, with antivirals or phototherapy used in severe cases.

2. Pityriasis rosea
Done by..Dr.Manar AlSanaa Ali

3. • An acute, self-limited, exanthematous skin disease
characterized by the appearance of slightly
inflammatory, oval, papulosquamous lesions on the
trunk and proximal areas of the extremities.
• Incidence is 170 cases per 100,000 persons per year.

4. Etiology
• A viral etiology for pityriasis rosea (PR) has been
hypothesized based upon the following
observations:
• ●PR is sometimes preceded by a prodrome.
• ●It occasionally occurs in small case clusters.
• ●It has not been shown to be associated with
bacterial or fungal organisms.
• reinforced by the finding of viral-like particles in PR
biopsy specimens examined with the electron
microscope.
• The most common viruses linked are human
herpesvirus-6 and -7.

5. Clinical Presentation
• Diagnosis of pityriasis rosea is based on clinical and
physical examination findings.

6. • Starts with a herald
patch on the trunk in up
to 90% of cases.
• The patch is
erythematous with
slightly elevated scaling
borders and a lighter
depressed center.
• It can measure 3 cm or
more in diameter and
may be the only skin
manifestation for
approximately two
weeks.

7. • Prodromal symptoms (e.g., general malaise, fatigue,
nausea, headaches, joint pain, enlarged lymph
nodes, fever, sore throat) present before or during
the course of the rash in 69% of patients.

8. • The generalized rash,
also known as the
secondary eruption,
presents on the trunk
along the Langer lines.
• May extend to the upper
arms and upper thighs.
• These lesions are
smaller than the herald
patch and can continue
to appear up to six
weeks after the initial
eruption.

9. • A rash on the back may
have a “Christmas tree”
pattern.

10. A rash on the upper chest
may have a v-shaped
pattern.
The mean duration of the
rash is 45 days; however,
it can last up to 12 weeks.
Moderate to severe
pruritus occurs in 50% of
patients.

11. RELAPSES
• Relapse rate low, between 1.8% and 3.7%.
• Typically occurs within five to 18 months of the
initial episode.
• Lacks a herald patch.
• lesions usually smaller or fewer than in the initial
episode.

12. SPECIAL
POPULATIONS
• Children:
• presents similarly to that in adults.
• Pruritus more often.
• Black children have more facial (30%) and scalp
involvement (8%), and postinflammatory pigmentary
changes (62%).
• Pregnancy:
• more susceptible to pityriasis rosea because of their
altered immune response.
• Increase in overall rate of spontaneous abortion. The rate
may reach to 57% in patients who developed pityriasis
rosea in the first 15 weeks of gestation.

13. Differential Diagnosis
• Lichen planus
• 1- to 10-mm, sharply
defined, flat-topped
violaceous papules
typically on wrists,
lumbar region, shins,
scalp, glans penis, and
mouth;
• lesions may be
asymptomatic

14. Tinea corporis
• Scaling, sharply
marginated plaques of
various sizes with or
without pustules or
vesicles along the
margins.
• lesions present with
peripheral enlargement
and central clearing,
producing an annular
configuration with
concentric rings or
arcuate lesions.

15. Tinea versicolor
• presents with
hypopigmented or
hyperpigmented
macules that are most
commonly located on
the neck and trunk.
• Unlike in PR, erythema
is absent or minimal.
• The scale in tinea
versicolor is fine, and
lesions lack the
peripheral rim of scale
that is often seen in PR.

16. Nummular eczema
• presents with intensely
pruritic, coin-shaped
plaques that may range in
size from 2 to 10 cm.
• Grouped small vesicles
and papules 4 to 5 cm in
diameter; round or coin-
shaped lesions with an
erythematous base and
distinct borders.
• Involvement of the
extremities is more
common.
• Serous exudate may be
visible in acute lesions.

17. Guttate psoriasis
• is a variant of psoriasis that
most frequently affects
children and young adults.
• Small, erythematous, scaly
plaques are distributed
primarily on the trunk.
• The scale tends to be
coarser than the scale
associated with PR,
• a herald patch does not
precede the eruption.
• frequently is associated with
a preceding streptococcal
infection.

18. Seborrheic dermatitis
• Orange-red or gray-
white skin with greasy
or white dry scaling
macules, papules, or
patches;
• diffuse scalp
involvement with
marked scaling;
• worsens in winter
because of dry
conditions;
• pruritus increases with
perspiration

19. Pityriasis lichenoides
chronica
• Red-brown papules with
central mica-like scales
randomly arranged on trunk
and proximal extremities with
chronic, relapsing course
• hypo- or hyperpigmentation
may be present after lesions
resolve.
• may be asymptomatic or
pruritic, and spontaneously
regress over the course of
weeks to months.
• Most commonly occurs in
children and young adults.
The disorder may persist for
years.

20. Pityriasis rosea–like eruption
associated with medications
• Adalimumab (Humira)
• Allopurinol
• Asenapine (Saphris)
• Arsenic compounds
• Atenolol
• Barbiturates
• Bismuth
• Bupropion (Wellbutrin)
• Captopril
• Clonidine
• Clozapine (Clozaril)
• Ergotamine
• Etanercept (Enbrel)
• Hepatitis B vaccine
• Imatinib (Gleevec)
• Influenza (H1N1) vaccine
• Interferon alfa-2a
• Isotretinoin
• Ketotifen (Zaditor)
• Lamotrigine (Lamictal)
• Lisinopril
• Nortriptyline (Pamelor)
• Omeprazole (Prilosec)
• Pneumococcal polysaccharide
vaccine (Pneumovax)
• Rituximab (Rituxan)
• Smallpox vaccine
• Terbinafine (Lamisil)
• Yellow fever vaccine

21. Treatment
• Patient/parent education
• information about clinical course, infectivity, and
relapse.
• Reassure typically spontaneously resolves within
two to three months, a low likelihood for
transmission, and does not recur in most patients.
• Pruritus:
• topical corticosteroids in the medium potency.
• Topical antipruritic lotions.
• oral antihistamines.

22. • Severe cases
• Acyclovir:
• a few small trials suggest that may accelerate
resolution of the clinical manifestations.
• 400 to 800 mg, five times per day for one week.
• Improvement is expected within one to two weeks.

23. • Phototherapy:
• Two small studies found improvements in severity and
symptoms in patients with pityriasis rosea who received
ultraviolet B phototherapy multiple times per week for up
to four weeks.
• Macrolid:
• The efficacy of oral erythromycin for PR is uncertain
based upon conflicting efficacy data for erythromycin and
the failure of randomized trials of other macrolides to find
benefit in PR.