++
Particularly in patients with darker skin types, pityriasis rosea
may be more papular and present in an “inverse pattern” (favoring
the body folds such as axillae).
++
Pityriasis rosea (PR) is a common, benign, self-limited whole
body rash with a seasonal prevalence that is clinically characterized
by a solitary “herald patch” lesion followed by
a whole body exanthem.
++
Synonyms Pityriasis rosea Gibert,
roseola annulata.
++
Age 10 to 35 years. Rare in <2
years.
++
Incidence 2% of all dermatology
visits.
++
++
Prevalence Common, especially in
fall and spring.
++
Etiology HHV6 and HHV7 have been
postulated, but not proven.
++
A solitary “herald” patch (Fig. 14-1) typically
precedes the exanthematous phase by 1 to 2 weeks. The exanthem develops
over a period of a week and self-resolves in 6 to 14 weeks without
intervention.
++
++
Herald Plaque Plaque with collarette
of scale (80%).
++
Exanthem Papules and plaques scale.
++
++
Size Herald patch: 1 to 10 cm.
Exanthem: 5 mm to 3 cm.
++
++
Arrangement Lesions follow the
lines of cleavage in a “Christmas tree” distribution
(Fig. 14-2).
++
++
Distribution Trunk > proximal arms,
legs. Head, face typically spared.
++
Sites of Predilection Axillae,
back, inguinal areas.
++
Headache, malaise, pharyngitis, or lymphadenitis (5%).
+++
Differential
Diagnosis
++
The diagnosis of PR is made on history of herald patch and clinical
findings. PR can be confused with tinea, secondary syphilis, guttate
psoriasis, tinea, parapsoriasis, pityriasis lichenoides (PL), seborrheic
dermatitis, drug eruption (gold, ACE inhibitors, metronidazole,
isotretinoin, arsenic, β-blockers, barbiturates, sulfasalazine,
bismuth, clonidine, imatinib, mercurials, methoxypromazine, d-penicillamine,
tripelennamine, ketotifen, and salvarson), and nummular eczema.
+++
Laboratory Examinations
++
Dermatopathology Small mounds of
parakeratosis, spongiosis, lymphohistiocytic infiltrate.
++
PR is typically asymptomatic and self-resolves in 6 to 14 weeks.
Atypical cases may have severe pruritis, have a more vesicular,
purpuric, or pustular presentation, or may last as long as 5 months. Once
cleared, it is uncommon for PR to ever recur.
++
Because PR is benign and self-limited, no treatment is needed.
In atypical PR or at-risk individuals, an RPR should be checked
because secondary syphilis can have a similar presentation. Pruritus
can be improved with topical steroids, ambient sunlight exposure,
oral antihistamines, and/or a 14-day course of oral erythromycin.
In more severe, prolonged cases, UVB light therapy or a short course
of oral steroids may be indicated.
+++
Pityriasis Lichenoides
++
Pityriasis lichenoides chronica may manifest as predominantly
hypopigmented patches, which are akin to postinflammatory hypopigmentation
from the primary lesions.
++
PL is a popular, clonal T-cell disorders, characterized by recurrent
crops of spontaneously regressing papules. Clinically, the spectrum
ranges from an acute form, pityriasis lichenoides et varioliformis
acuta (PLEVA), to a more chronic form, ityriasis lichenoides chronica
(PLC).
++
Synonyms Acute guttate parapsoriasis,
parapsoriasis varioliformis, Mucha-Habermann disease, guttate parapsoriasis
of Juliusberg.
++
++
1. PLEVA: Any age.
2. PLC: Adolescents and adults.
++
++
Etiology Clonal T-cell disorder.
++
The etiology of PLEVA and PLC is unclear. Theories include an
infectious course, an autoimmune mechanism, or a hypersensitivity
reaction to drugs. PLEVA shows a predominance of CD8+ T
cells. PLC shows a predominance of CD4+ T cells.
++
Self-resolving skin lesions tend to appear in crops over a period
of weeks or months. Cutaneous lesions are usually asymptomatic,
but may be pruritic or sensitive to touch.
++
Type PLEVA: Papules (Fig. 14-3),
vesicles, pustules, scale PLC: Papules, crusts, scars.
++
++
Color PLEVA: Pink, red. PLC: Red,
brown. White scars.
++
Distribution Generalized distribution
(Fig. 14-4), including palms, soles mucous membranes.
++
++
Rare fever, malaise, and headache.
+++
Differential
Diagnosis
++
PLEVA can be confused with lymphomatoid papulosis, vasculitis,
drug reaction, bites, scabies, varicella, folliculitis, impetigo,
or prurigo nodularis. PLC can be confused with parapsoriasis, lichen
planus (LP), guttate psoriasis, PR, or secondary syphilis.
+++
Laboratory Examinations
++
Dermatopathology Skin biopsy shows
epidermal spongiosis, keratinocyte necrosis, vesiculation, ulceration,
and exocytosis. There is also dermal edema, a wedge-shaped inflammatory
cell infiltrate extending to deep reticular dermis; hemorrhage;
vessels congested with blood, and swollen endothelial cells.
++
PL skin lesions continue to appear in crops, but both disorders
tend to have a relapsing benign course. PLEVA may last a few weeks
to months, and PLC may last years. They should always have continued
follow-up because rare cases have been reported to progress to cutaneous
T-cell lymphoma (CTCL).
++
PL episodes are self-limited and most patients do not require
any therapeutic intervention. For symptomatic relief, ambient sunlight
exposure, topical steroids, topical coal tar, oral antihistamines,
oral tetracycline, or oral erythromycin have had reported success.
In more severe, prolonged cases, UVB light therapy or a short course
of oral steroids/methotrexate may be indicated. Follow-up
of these children (acutely: every few months, then chronically:
an annual skin examination) is needed to monitor for possible CTCL.
++
Lichen sclerosis (LS) is a benign mucocutaneous disorder, characterized
by sclerotic white plaques with epidermal atrophy.
++
Synonyms Guttate morphea, guttate
scleroderma, white-spot disease, lichen sclerosis et atrophicus,
balanitis xerotica obliterans (BXO;, lichen sclerosis of the penis)
++
Age 1 to 13 years. 70% before
age 7 years. Also 50- to 60-year-old women.
++
++
Etiology Genetic predisposition.
HLA-DQ7 association.
++
LS is an inflammatory dermal disease that causes white scarlike
atrophy. In non genital skin, it may be pruritic or cosmetically
upsetting. Asymptomatic genital lesions may be present for years prior
to detection. Often the skin findings are mistaken for sexual abuse
in young children and are thus brought to medical attention. Older
patients are diagnosed when atrophic changes are noted by a gynecologist
or internist during pelvic examination. Spontaneous involution occurs
in children more than adults.
++
++
Color Papules: pink. Plaques: ivory “mother-of-pearl”.
++
Nongenital Distribution Trunk,
periumbilical, neck, axillae; flexor surface of wrists.
++
Genital Distribution Females: “figure-of-eight” or “hourglass” perivulvar/perianal/perineum
(Fig. 14-5). Males: prepuce and glans (Fig. 14-6).
++
++
++
Oral Mucosa Buccal, palate, tongue:
bluish-white plaques, erosions, macerated lesions.
+++
Differential
Diagnosis
++
LS can be confused with morphea, lichen simplex chronicus, discoid
lupus erythematosus, leukoplakia, LP, condyloma acuminatum, intertrigo
candidiasis, pinworm infestation, or bacterial vulvovaginitis. Most
importantly, genital LS in children can be confused with sexual
abuse which is often what brings the lesions to medical attention.
+++
Laboratory Examinations
++
Dermatopathology Early lesions:
hyperkeratosis, follicular plugging, edema with a lymphocytic bandlike
infiltrate subepidermally. Later lesions: epidermal atrophy, band
of homogenized dermal collagen below epidermis.
++
The prognosis is good for patients with childhood onset. Most
clear in 1 to 10 years and 60% to 70% improve
substantially by puberty. A small number persist into adulthood.
Persistent lesions can be sensitive especially while walking; pruritus
and pain can occur especially if erosions are present. Other complications
include dysuria; dyspareunia and stricture of the introitus. In
males, chronic BXO can lead to phimosis and recurrent balanitis.
Rarely, chronic scarred lesions can show malignant degeneration.
++
1. Topical steroids are effective in the treatment
of genital LS. A short course of medium or strong steroid cream
once or twice daily for 12 to 24 weeks has the best reported clinical
outcomes. Intralesional steroids have also been used.
2. Emollients and antipruritic agents can also be tried for symptomatic
relief.
3. Topical calcineurin inhibitors (tacrolimus 0.1% ointment
or pimecrolimus cream) have reported success.
4. Topical vitamin D (calcipotriene cream) and vitamin A have
anecdotal success.
5. Use of 2% testosterone propionate in petrolatum or
1% progesterone (100 mg/30 g of petrolatum) can
be tried, but with little success.
6. Surgical interventions may be warranted for GU complications
such as stricture of the introitus in females and phimosis in males.
7. Involution in adults is uncommon and LS needs to be chronically
monitored for progression toward malignant degeneration (4.4% of
adult cases). In adults, new nodules or ulcers that persist for
weeks warrant a skin biopsy to rule out leukoplakia or carcinoma.
++
Lichen planus (LP) is an inflammatory disorder of the skin and
mucous membranes with characteristic flat-topped (Latin planus, “flat”),
violaceous, shiny, pruritic papules, and milky-white papules in
the mouth.
++
Synonyms Lichen ruber planus
++
Age Rare in children (4%).
More common in 30 to 60 years old.
++
++
Prevalence 1% of the population.
++
Etiology Unknown. Triggers: viral
infections, autoimmune diseases, medications, vaccinations, and
dental materials.
++
Genetics Sporadic. Rare familial
cases.
++
LP is thought to be caused by T-cell-mediated autoimmune damage
to basal keratinocytes, which have been altered by viruses, medications,
or other allergens. Several exogenous antigens thought to trigger
LP include viruses (hepatitis C, transfusion-transmitted virus,
HHV-6, HHV-7, HSV, VZV), vaccinations (hepatitis B), bacteria (Heliobacter
pylori), dental materials (amalgam, mercury, copper, gold), drugs
(captopril, enalapril, labetalol, methyldopa, propanolol, chloroquine, hydrochloroquine,
quinacrine, chlorothiazide, hydrochlorothiazide, gold salts, penicillamine,
quinidine), autoimmune diseases (HLA-B27, HLA-B51, HLA-Bw57, HLA-DR1,
HLA-DR9).
++
LP is a pruritic eruption involving the wrists, forearms, genitalia,
distal lower extremities, and presacral areas. Clinical variants
range from annular, bullous, hypertrophic, linear, to ulcerative lesions,
which may spontaneously remit, or persist for life.
++
++
++
++
Color Violaceous, with white lines
(Wickham’s striae) (Fig. 14-7).
++
++
Arrangement Grouped, linear, annular,
or disseminated.
++
Distribution Wrists, forearms,
genitalia, distal lower extremities, and presacral areas.
++
Mucous Membranes White papules/lines
on the buccal mucosa, tongue, lips (60%).
++
Scalp Atrophic scalp skin with
alopecia.
++
Nails Destruction of the nail fold
and nail matrix (10%) (Fig 14-8).
++
+++
Differential
Diagnosis
++
LP can be a reaction pattern to various exogenous antigens. Thus,
identifying potential triggers such as viruses, medications, vaccinations,
immunizations, and dental materials is important, before labeling
the condition idiopathic LP. Other diseases that resemble LP include
lupus erythematosus, lichen nitidus, lichen striatus, lichen sclerosis,
PR, and psoriasis.
+++
Laboratory Examinations
++
Dermatopathology Hyperkeratosis,
hypergranulosis, irregular acanthosis, liquefaction degeneration
of the basal cell layer, and a bandlike mononuclear infiltrate that
hugs the epidermis.
++
Spontaneous resolution of LP in weeks is possible; two-thirds
of patients self-resolve after 1 year. LP lesions may also persist
for years, especially on the shins and in the mouth where the mean duration
is 5 years. Careful follow-up for oral LP is recommended since it
has the potential for malignant transformation (1%–2%).
++
Therapies for LP include the following:
++
1. Topical corticosteroids with or without occlusion
or intralesional steroids. Patients should be forewarned that occlusion
increases the steroid strength and cautioned about steroid side
effects.
2. Topical calcineurin inhibitors (tacrolimus 0.1% ointment
or pimecrolimus cream) have reported success for some cases of refractive
oral LP.
3. Systemic steroids (prednisone 1–2 mg/kg/d
divided qid-bid for 5–14 days) can be used in severe cases,
and only in short courses.
4. Systemic retinoids (acitretin 30 mg/kg/d
or etretinate 50 mg/d in adult-sized patients for 8 weeks)
can be used in difficult cases.
5. Phototherapy with narrowband UVB or PUVA (psoralen plus artificial
UVA exposure) may be used in older children or in generalized, severe,
resistant cases.
6. Systemic griseofulvin, metronidazole, sulfasalazine, cyclosporine,
mycophenolate mofetil, and thalidomide have had anecdotal reported
successes.
++
Lichen nitidus is a benign dermatosis commonly seen in childhood,
characterized by asymptomatic, small, flesh-colored pinpoint papules
located on the flexor surface of the arms and wrists, lower abdomen,
genital, and submammary region.
++
Age Preschool and school-age children.
++
++
++
Etiology Possibly a form of LP.
++
Because of ultrastructural and immunophenotypic studies, lichen
nitidus is thought to share a similar pathogenesis to LP: a T-cell-mediated
autoimmune damage to basal keratinocytes.
++
The skin lesions appear suddenly and are typically asymptomatic
(some cases have pruritus). Lesions may regress spontaneously after
weeks to months but other cases persist for years.
++
Type Papules. Fine scale.
++
Color Flesh-colored, pink.
++
Size Pinpoint to pinhead in size
(Fig. 14-9).
++
++
Shape Round or polygonal.
++
Sites of Predilection Flexor surface
of the arms, anterior wrist surface, lower abdomen, shaft and glans
of the penis, and breasts.
++
Distribution Linear lesions in
lines of trauma (Koebner reaction). Generalized form.
++
Nails (10%) Pitting, ridging,
splitting.
+++
Differential
Diagnosis
++
Lichen nitidus can be confused with LP, lichen striatus, lichen
sclerosis, popular eczema, psoriasis, flat warts, keratosis pilaris,
lichen spinulosa, or an id reaction.
+++
Laboratory Examinations
++
Dermatopathology Sharply circumscribed
nests of lymphocytes and histiocytes in the uppermost dermis (often
confined to two to three dermal papillae) with overlying thin, scaling
epidermis. Dermis and epidermis are often detached at central portion
of lesion. Rete ridges extend down around the infiltrate in a “claw-and-ball”-like
manner.
++
Typical lichen nitidus lesions self-resolve in 1 to 2 years.
In other instances, lesions may persist for several years despite
treatment. There are no reports of associated systemic disease.
After papules clear, skin is without atrophy or pigmentary changes.
++
Given the benign, self-limited clinical course of lichen nitidus,
no treatment is necessary. In rare cases with pruritus, topical
corticosteroids with or without occlusion may be helpful. Patients should
be forewarned that occlusion increases the steroid strength and
cautioned about steroid side effects. Topical calcineurin inhibitors
have also had reported success.
++
In severe, refractory, generalized forms of lichen nitidus, narrowband
UVB, PUVA, oral etretinate, and oral itraconazole have anecdotal
reported success.
++
A benign, self-limited dermatitis characterized by a unilateral
papular eruption on the extremity of a child in a Blaschkoid distribution.
++
Synonyms Linear lichenoid dermatosis,
Blaschko linear acquired inflammatory skin eruption (BLAISE).
++
Age Onset 4 months to 15 years
of age. Median age: 2 to 3 years.
++
++
++
Seasonal Prevelance Spring and
summer.
++
Etiology Somatic mosaicism. ? Viral
trigger.
++
Lichen striatus appears suddenly, reaches its maximum extent
within several days to weeks and then regresses spontaneously within
6 to 12 months. Lesions are asymptomatic. Nail involvement can lead
to onycholysis splitting, fraying, and nail loss.
++
Type Papules, slight scale.
++
++
Color Hypopigmented, pink or red.
++
Shape Small, flat-topped lesions.
++
Arrangement Linear following Blaschko
lines (Fig. 14-10).
++
++
Distribution Extremities, face,
neck, trunk, and buttocks.
++
Sites of Predilection Often unilateral
on an extremity.
+++
Differential
Diagnosis
++
Characteristic Blaschko linear appearance of lesions located
on an extremity or other common site is indicative of lichen striatus.
Lichen striatus needs to be differentiated from other linear disorders
such as nevus unius lateris, psoriasis, lichen nitidus, an epidermal
nevus, or linear LP.
+++
Laboratory Examinations
++
Dermatopathology A dense perivascular
or bandlike lymphohistiocytic infiltrate appears in the dermis.
The epidermis reveals a small lymphocytic invasion with focal areas
of acanthosis, parakeratosis, and spongiosis.
++
Lichen striatus is typically an asymptomatic, self-limiting disorder
of short duration (6–12 months).
++
Given the benign, self-limited clinical course of lichen striatus,
no treatment is necessary. In rare cases with pruritus, topical
corticosteroids with or without occlusion may be helpful. Patients should
be forewarned that occlusion increases the steroid strength and
cautioned about steroid side effects.