Disorders of Hypopigmentation (Leukodermas) Flashcards
Most significant ocular abnormality assoc with vitiligo
Uveitis
Vogt-Koyanagi-Harada Syndrome
Autoimmune disorder characterized by:
- Uveitis
- Aseptic meningitis
- Otic involvement
- Poliosis
- Vitiligo
- Alopecia
Alezzandrini Syndrome
Poliosis, facial vitiligo, deafness, all occurring on the same side as unilateral visual changes
Most common type of childhood vitiligo
Vitiligo vulgaris; increased segmental vitiligo seen in children compared to adults
Treatment options for vitiligo
Sunscreens, cosmetics, NB-UVB (1st choice for generalized vitiligo), PUVA, topical corticosteroids/immunosuppressants, topical calcipotriol, surgical tx, micropigmentation (tattooing), excimer laser, depigmentation
Piebaldism
Genetic Mutation: cKIT (autosomal dominant)
Features: Leukoderma (favors central anterior trunk, mid-extremities, central forehead, midfrontal portion of scalp w/ resultant white forelock)
Waardenburg Syndrome (Features)
-Achromia of hair and/or skin; congenital deafness, partial/total herochromia irides, medial eyebrow hyperplasia (synophrys), broad nasal root, dystopia canthorum
Types of Waardenburg Synrdome
WS1 (AD): PAX3; poliosis (white forelock), craniofacial abnormalities, dystopia canthorum
WS2 (AD): MITF, SLUG; deafness, “auditory-pigmentary”
WS3 (AD/AR): PAX3; white forelock, craniofacial abnormalities, dystopia canthorum; axial limb defects (hypoplasia, syndactyly)
WS4 (AD): SOX10, EDN3, EDNRB; white forelock, craniofacial abnormalities, dystopia canthorum, Hirschsprung disease
Oculocutaneous Albinism (inc types)
OCA 1A/1B: 40% of OCA; TYR gene (a=absent; b= reduced activity); strong predisposition to skin cancer
OCA1TS: temp sensitive mutant; normal synthesis in cool body parts (arms/legs)
OCA 2: 50% of OCA; P gene; reduction in eumelanin but less effect on pheomelanin; nevi, light brown hair, nystagmus; affects 1% Prader-Willi or Angelman Syndrome
OCA 3: “rufous”; TYRP1; skin mahogany brown with slight reddish hue
OCA 4: SLC45A2; most common OCA in Japan
Ocular Albinism
Gene: OA1; X-linked recessive; substantial reduction in visual acuity
Hermansky-Pudlak Syndrome
Gene: HPS1 etc; AR; predominant Puerto Ricans
Features: pigmentary dilution; nystagmus; decreased visual acuity; bleeding tendency (plts missing granules); tooth extraction; childbirth caution; interstitial pulmonary fibrosis; granulomatous colitis (HPS1, HPS4); lifespan 30-50yrs
Griscelli Syndrome
Gene:
GS1 Myosin Va…..neurologic impairment
GS2 Rab27A…..immune and heme abn (cant release lysosom granules)
GS3 MLPH….least severe; no immune/neuro
Features: pigmentary dilution; silvery gray hair; no lysosomal granules on smear (CH does); poor prognosis (die w/in 1st-2nd decade)
Elejalde Syndrome
Gene: (AR)
Features: silvery gray hair; severe CNS dysfxn; forme fruste of GS1?
Chediak-Higashi Syndrome
Gene: (AR) LYST
Features: OCA with silvery gray hair, photophobia, nystagumus, ocular hypopigmentation, BLEEDING DIATHESIS (decreased plt dense granules), progressive neuro dysfxn, severe immunodeficiency
Childhood CHS (severe; “accelerated phase” w fever, anemia, neutropenia, LP syndrome; fatal unless BM Tx
Adult CHS: milder clinical
Hallmark: Giant peroxidase-+ lysosomal granules in netrophils
Histologic Hallmark: giant melanosomes w/in melanocytes
Tuberous Sclerosis
Gene: (AD) TSC1 (hamartin) and TSC2 (tuberin)
Features: hypomelanotic “ash leaf” macules, adenoma sebaceoum, seizures, MR
Hypomelanosis of Ito
-streaks/whirls/hypopigmentation along Blashko’s lines on trunks/limbs; 30% w/ CNS/eye/MSK and/or heart defects
Causes of Nutritional Hypomelanosis
Kwashiorkor; copper or selenium deficiency; Vit B12 def, folic acid dev, or pellagra
Cause of Pityriasis Versicolor
Malassezia (produces azelaic acid which is comp inhib of tyrosinase)
Chemical/Pharmacologic Hypomelanosis
Phenols/Catechols Sulfhydryls Hydroquinone Topical/IL Corticosteroids Gleevec (imatinib)
Causes of Acquired Diffuse Hypopigmentation
Hypothyroidism; Hypopituitarism
Hypogonadism
Selenium/Copper Def
Chronic Hemodialysis (Skin/hair)
Bier’s spots
small irregular apparently hypopigmented macules (usually arms/ legs of young adults); reticulated appearance w/ surrounding skin erythematous; vascular anomaly (vasoconstriction in pale areas and venodilation in eryth skin)
Woronoff’s Ring
blanched halo surrounding psoriatic lesions after phototherapy or topical tx
Nevus anemicus
Unilateral pale area w/ irregular outline; caused by decrease blood flow through capillaries in dermal papillae (localized hypersensitivity of blood vessels to catecholamines)
Vasospastic macules
pale macules seen on extremities due to localied vasoconstriction (young women)
Idiopathic guttate hypomelanosis
common, asymptomatic, increase with age
Leukoderma Punctatum
multiple punctiform hypopigmented achromic spots after several months of PUVA (and UVB)
Vagabond’s Leukomelanoderma
due to dietary def, lack of cleanliness, heavy infestation w/ Pediculus humanus; light brown hyperpigm at shoulder/waist; neck and back dotted with depigmented macules
Progressive Macular Hypomelanosis of the Trunk
young women; tropical climate; poorly defined nummular non-scaly hypopigmented macules and patches
Hair Hypomelanosis
poliosis (circumscribed area of white hair); canities (gray hair); occurs in aging and due to defective maintenance of melanocyte stem cells
PREMATURE: assoc with pernicious anemia, hyper/hypothyroidism, osteopenia, progeria, pangeria
