Ch. 13 - White spots Flashcards
What can cause decreased melanin pigmentation?
- a reduction in the number of melanocytes or
- a decrease in their melanin production
What are white spots in the skin a result of?
decreased melanin pigmentation
What should white spots be examined for?
- partial versus complete pigment loss
2. presence or absence of scale
White spots are seen more easily by the use of what?
Wood’s light
an idiopathic hypopigmentary condition that appears clinically as white patches surmounted by fine, ‘bran-like’ scales.
pityriasis alba
Who is pityriasis alba most commonly seen in?
darkly pigmented children
pityriasis alba is symptomatic or asymptomatic?
asymptomatic
What does pityriasis alba most often present as?
a 1-4 cm white patch with a fine, powdery scale.
What is pityriasis alba most often misdiagnosed as?
tinea versicolor
the result of melanocyte destruction or suppressed melanin production secondary to inflammation of the skin that appears as a hypopigmented macule.
post-inflammatory hypopigmentation
What are causes of post-inflammatory hypopigmentation?
- physical trauma
- chemicals
- skin diseases
What are some physical agents that can induce post-inflammatory hypopigmentation?
X-irradiation & frostbite
What is the therapy for post-inflammatory hypopigmentation?
none; repigmentation will sometimes occur
a superficial fungal infection of the stratum corneum that results in altered pigment in the epidermis, with the lesions appearing as finely scaling patches
tinea versicolor
What is the most common color that the epidermis becomes with tinea versicolor?
white
T/F:Tinea versicolor is an uncommon disease, affecting only 1% of the general population.
FALSE: (it’s a common disease)
Where is the incidence of tinea versicolor higher?
in tropical climates
What age group is tinea versicolor most common among?
young adults
Tinea versicolor is occasionally associated with ___, but more often is asymptomatic.
mild pruritis
What is the appearance of the lesions upon physical examination in patients with tinea versicolor?
round, hypopigmented, slightly scaling patch that often starts as multiple small follicular macules but become confluent.
What does the use of a wood light reveal in patients with tinea versicolor?
the scales fluoresces pale yellow or orange (but not universal or should be relied on)
Where is the usual distribution of tinea versicolor in patients?
neck, trunk, and upper arms (face & legs involved in tropical climates)
In adults, the white spots of tinea versicolor is most often misdiagnosed as _____.
vitiligo
Tinea versicolor appearing as pink or tan scaling patches on the chest may be misdiagnosed as _____.
seborrheic dermatitis
What is the only examination that works to diagnose tinea versicolor?
KOH preparation
Which skin disorder gives the appearance of spaghetti & meatballs upon KOH preparation?
tinea versicolor
What is the simplest most effective therapy for tinea versicolor?
oral fluconazole
After initial therapy, how long does it take for the white spots to retain pigment?
months
What is tinea versicolor caused by?
infection with the fungus Malassezia
a rare, autosomal dominantly inherited, neurocutaneous disorder with several skin manifestations, including macules, caused by mutations in one of two genes, tsc1 & tsc2.
tuberous sclerosis
What is the classic triad of tuberous sclerosis?
seizures, mental retardation, and adenoma sebaceum
a misnamed disorder consisting of angiofibromas that begin in childhood and appear clinically as red papules on the face.
adenoma sebaceum
In which skin disorder do the white spots appear as a thumbprint or ash leaf - oval at one end and pointed at the other?
tuberous sclerosis
Where are the white spots of tuberous sclerosis most often found?
on the trunk and less often the face and extremities
T/F: All infants with a seizure disorder should be screened for white spots with a Wood’s light examination.
TRUE
an acquired condition in which functional melanocytes disappear from affected skin; lesions clinically appear as totally white, non-scaling, sharply demarcated macules.
vitiligo
Higher incidence rates of vitiligo occurs in what population?
dark-skinned individuals within the 10-30 yr. age group
Vitiligo is usually asymptomatic/symptomatic?
asymptomatic
What is the primary lesion of vitiligo present as upon physical examination?
a white macule that is usually totally depigmented
T/F: scale is present with vitiligo
FALSE (NO scaling)
Where are the most common areas affected by vitiligo?
the extensor bony surfaces (backs of hands, elbows, and knees) and the periorificial areas (around the mouth, eyes, rectum, and genitalia)
T/F: the laboratory is not helpful for diagnosing vitiligo?
TRUE
T/F: There is no cure for vitiligo?
TRUE
What is the initial therapy for vitiligo?
narrow-band UVB or topical steroids
What cells are absent in patients with vitiligo?
melanocytes
What are 3 proposed pathologic mechanisms for vitiligo?
- autoimmune
- neural
- self-destruction
What is the most common type of cutaneous T-cell lymphoma?
Hypopigmented Mycosis Fungoides
Where do skin lesions occur in patients with hypopigmentated mycosis fungoides?
the buttocks and trunk and can evolve into plaques or tumors
A common condition in women that is under-recognized where lesions appears as well demarcated, small macules, like ‘sprinkled confetti’.
idiopathic guttate hypomelanosis
Where does idiopathic guttate hypomelanosis most commonly appear on the body?
the shins, but may also be found on the forearms
What skin disorder is caused by the acid-fast organism Mycobacterium leprae?
Leprosy
Where is leprosy endemic?
south-eastern USA & Hawaii
What is the earliest sign of leprosy?
a solitary hypopigmented macule
What is the earliest sensory change with leprosy?
loss of feeling to light touch and cold in the hands and feet.
Which stain is used to confirm a diagnosis of leprosy?
Fite stain
