Disorders of Hypopigmentation (Leukodermas) Flashcards
(29 cards)
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)
