Vitiligo and other disorders of hypopigmentation Flashcards
What is the average age of onset for vitiligo?
20 years old, women may have earlier onset
What is the pathogenesis of vitiligo?
Genetic and non-genetic causes
The process of this destruction is somewhat unclear: hypotheses include autoimmune-mediated destruction, intrinsic defects in the melanocytes, cytotoxic metabolites, oxidative stress, or biochemical anomalies
Primary problem is the absence of functional melanocytes due to destruction of the melanocytes
Clinical features of vitiligo?
Presents as a well-circumscribed, depigmented, asymptomatic patch or macule
Differences between hypopigmentation and depigmentation on woods lamp?
Woods lamp can help show depigmentation vs hypopigmentation. Depigmentation almost glows with the woods lamp, think how teeth look under blacklight. Hypopigmentation is not as intense
What are the most common sites of vitiligo?
Fingers, wrists, axillae, groin, genitals, and facial (around the mouth or eyes)
these areas can enlarge over time
Koebner phenomenon occurs
What are the different clinical classifications of vitiligo?
localized (segmental can be a subset, usually in children); focal; or mucosal), generalized (most common), or universal (>80% of skin)
What are the most common disease associations with vitiligo?
thyroid dysfunction (most common), DM1, Addison’s disease, pernicious anemia, halo nevi, alopecia areata, and uveitis
What is Vogt-Koyanagi-Harada (VKH) syndrome?
Bilateral granulomatous uveitis, aseptic meningitis, dysacousia/deafness, poliosis/alopecia, and vitiligo
What is Alezzandrini syndrome?
Unilateral facial vitiligo/poliosis with visual/hearing impairment on the same side
What is Kabuki syndrome?
Developmental delay; congenital heart defects, skeletal anomalies/short stature, in addition to autoimmune issues (vitiligo)
Treatment of vitiligo?
Topical steroids, TCI, topical vitamin D analogs, NB-UVB, phototherapy/excimer laser, systemic immunosuppressants, surgical therapies, and depigmentation
What are some bad prognostic indicators for vitiligo?
Mucosal involvement, family history, koebnerization, and non-segmental disease
Good prognostic indicators in vitiligo?
Recent onset, younger, and lesions of face/neck/trunk
When pigment does return after treatment/as part of the disease course in vitiligo, where does the pigment come from?
Follicular regimentation is seen which represents the migration of melanocytes from hair follicles is the typical appearance
Which form of vitiligo is more common?
Generalized or localized
Generalized
What types of vitiligo is more associated with other autoimmune disease?
The generalized form
Are halo nevi associated with vitiligo?
Yes
What is one important histologyic difference between hypopigmented MF vs vitiligo?
The T-cells are more lichenoid in the MF, in the vitiligo they are more targeted to that area, just attaching the melanocytes
What is the clinical apperence of a halo nevus?
Melanocytic nevus w/ surrounding well demarcated hypo-depigmentated skin
What is the most common location for halo nevus?
Usually on the upper back
What is the histology of a halo nevus?
Dense band of lymphocytes and macrophages surrounidng nests of melanocytes
Prognosis of halo nevi?
Many regress over several months
Should do full skin-exam because can be a marker for melanoma
What are chemical leukodermas?
Hypo or depigmentation of the skin or hair that results from chemical or pharacologic agents
What are some chemicals/things that can cause chemical leukodermas?
Phenols: derivative monobenzyl ether of hydroquinone leads to depigmentation
Catechols and Sulfhydryls
topial steroids, hydroquinone, and imatinib can lead to hypopigmentation
Physical injuries from burns, freezing, radiation, lasers, surgery, UV and truama can damage melanocytes leading to hypo or depigmentation
What is idiopathic guttate hypomelanosis?
Increased incidence w/ age and is more common in skin of color
- Thought to be from aging, sun exposure and genetics
- it presents as well-demarcated areas of hypo-depigmented macules that are more common on the extremitites
In whom is progressive macular hypomelanosis most commonly seen in?
Darker skinned women from tropical regions
What is the clinical presentation of progressive macular hypomelanosis?
Ill-defined, hypopigmented macules/patches on the trunk/upper extremities w/ no scale which can become confluent
What are the treatments for progressive macular hypomelanosis?
Benzoyl peroxide, topical clindamycin, and UVA irradiation
There is believed to be a connection between C. acnes and this condition
What is a nevus anemicus?
Pale, tyicpally unilateral area of skin (5-10cm) with irregular outline
- It is present from birth and typically found on the trunk
What is a nevus anemicus caused from?
Decreased blood flow/vasoconstrition in the dermal papilla due to localzed hypersensitivity of blood vessels to catecholemines
- it is most noticible w/ heat or emotional stress that cases surrounding vasodiatlion
What will be seen on diascopy for a nevus anemicus?
Causes blanching of surrounding skin, nevus no longer visable
What are some differences between a nevus anemicus and a nevus depigmentosus?
Nevus depigmentosus: develops in infancy (as opposed to present at birth), has distinct midline demarcation and less distinct lateral borders, and on disascopy it does not disappear when pushed down upon
It is an actual decreases in melanosomes in melanocytes and keratinocyts
What is the histopathology of nevus depigmentosus?
Normal number of melanocytes with decreased melanosomes in the melanocytes and keratinocytes
What is segmental pigmentation disorder?
Is a variant of nevus depimentosus that can have a checkerboard pattern of hypopigmentation or hyperpigmentation
What is hypomelanosis of Ito?
Hypopigmentation along Blaschko’s lines due to mosaicism (linear nevoid hypopigmentation)
What is the most common location and time of onset for hypopigmentation of Ito?
Present at birth or early infancy/childhood
- Affects trunk and extremities more commonly can be unilateral or bilateral
What is important to remember in regards to disease assocations with hypomelanosis of Ito?
30% of pts have CNS, MSK or ophthalmologic abnormalities
What is the clinical progression/prognosis of segmental vitiligo?
Segmental vitiligo has a rapid onset but is often more stable. These pts don’t tend to progress to generalized vitiligo and the lesions may be responsive to therapies like topical calcineurin, steroids, or narrow-band UVB therapy
