what is the pathophysiology of staph scalded skin syndrome?
Staph aureus exfoliative toxins. The toxins act at the zona granulosa of the epidermis, causing cleavage of desmoglein 1 complex, an important protein in desmosomes, the organelles that help anchor keratinocytes to each other. This results in the formation of fragile, tense bullae that often are no longer intact by the time of presentation
What is Incontinentia pigmenti?
X-linked dominant disorder
IKBKG gene on Xq28
Characterised by
- Blistering at birth, Wart like rash later, then macular hyperpigmentation and late linear hypopigmentation
- Alopecia
- Hypo-odontia, peg teeth, persisting milk teeth
- Neurological - Cerebral atrophy, DD
- Eye problems - cataracts,
- Breast hypoplasia/supernumery nipples
- Skeletal and limb problems
- PPHN
Diagnosed on skin biopsy.
What is the gene defect and inheritance of epidermolysis bullosa?
AD
Keratin 5 and 14.
What is DRESS syndrome?
Drug rash with eosinophilia and systemic symptoms.
- Classically seen 1-6 week after initial exposure to anticonvulsant or others (allopurinol, sulfonamides, antibiotics)
Triad of
RASH (pruritic, diffuse, erythematous to urticarial eruption. Exfoliation uncommon.
FEVER
HEPATITIS
Eosinophilia in 30%. Atypical lymphocytosis common.
Late onset thyroiditis and hypothyroidism may occur.
DDx: SJS, Viral, MAS/HLH, GVHD.
Rx: Stop med. Oral steroids.
When do you start to see GVHD?
1-3 weeks after transplant.
What other situations do you see GVHD apart from transplant?
- Immunodeficiency and receiving non-irradiated blood products
- Sick neonates receiving non-irradiated blood
- Neonates with immunodeficiency with maternal lymphocytes.
What is the characteristic of chronic GVHD?
Lichenoid eruptions.
What conditions give you redundant neck skin?
Turner Noonan Down Klippel-Feil syndrome Monosomy 1p36
What gives you amniotic bands?
Abdominal trauma
Amniocentesis
Ehlers-Danlos
Osteogenesis imperfecta
What is the limb-body wall complex?
Vascular disruption early in development. Includes at least 2 out of 3: encephalocoe/exencephaly with facial clefts, thoracoschisis/abdominoschisis and limb defects.
What can ear pits/sinus tracts be due to?
imperfect fusion of the tubercles of the 1st and 2nd branchial arches (unilateral/bilateral)
What is branchio-otorenal dysplasia 1 syndrome?
AD condition affecting EYA-1 gene. External ear malformations Branchial fistulas Hearing loss Renal anomalies.
Which branchial arch is the accessory tragi derived from?
1st branchial arch.
What is the most common branchial cleft?
2nd branchial cleft.
What is aplasia cutis congenita?
Congenital absence of skin.
Aplasia cutis + blistering skin + nail deformity makes you think….
Epidermolysis bullosa.
What is dyskeratosis congenita?
Triad of
- Reticulated hyperpigmentation of skin
- Dystrophic nails (1st sign in childhood)
- Mucous membrane luekoplakia.
At risk of cancer, especially SCC.
Premature aging ++
What are the features of anhidrotic (hypohidrotic) ectodermal dysplasia?
X-linked/AR/AD. (x-linked most common)
problems with
- Absence of sweat glands
- Abnormal dentition
- Hypotrichosis.
What problems do people with ED run into?
- Can’t sweat -> fever.
- Dentition
- GORD + FTT
- Eye problems (can’t produce tears)
- Dysgammaglobulinemia (X-linked/AD)
What are port-wine stains?
Dilated dermal capillaries.
Macular. Purple and variable size.
What is Sturge-Weber syndrome?
Glaucoma (early screening important) Leptomeningeal venous angioma Seizures Hemiparesis contralateral to facial lesion Intracranial calcification.
What is Klippel-Trenaunay syndrome?
Nonheritable.
Skin changes (capillary malformation usually)
Soft tissue and bony hypertrophy (usuallylower limb)
Venous system absent/hypoplastic.
What is the immunohistochemical marker of haemangiomas?
GLUT-1
What is the natural history of haemangiomas?
May be red/blue/pale at first.
Develop period of telangiectasia bfore expansion.
Most involute by 5 years
90-95% involute by 9 years.
Which area of haemangioma persist longest?
Lip
What endocrine problem is associated with large hemangiomas?
Hypothyroidism. Due to type 3 iodothyronine deiodinase.
What are syndromes associated with haemangiomas?
PHACES
Gorham (cutaneous hemangiomas with massive osteolysis)
Bannayan-Riley-Ruvalcaba (macrocephaly lipoma, hemangiomas)
When do RICH (rapidly involuting congenital haemangiomas) involute?
1 year. No rapid growth phase.
When do telangiectasias form in ataxia telangiectasia?
- First on bulbar bconjunctivae, later on nasal bridge, malar areas, hard palate, upper anterior chest, antecubital/popliteal fossa.
What is hereditary haemorrhagic telangiectasia? (osler-weber-randu disease)
AD.
Recurrent epistaxis. Characteristic skin/mucous membrane lsions.
Cx: massive haemorrhage (from everywhere)
Stroke (from AVM in lungs.
What is the rash like in Fabry disease?
Angiokeratoma corporis diffusum.
Angiokeratomas appear before puberty, usually around genitalia, hips, bum, thigh, umbi, inguinal areas. 0.1-3mm red to blue/black papules.
Accumulation of ceramide trihexoside in tissues (particularly vascular endothelium) and excretion in urine.
What conditions are associated with cafe au lait spots?
Rocky made new veranda friends but they are gay parrots
Russel-Silver McCune-Albright, MEN type 1, Marfans NF-1, Noonan's Von-Hippel Lindau Fanconi anemia Bloom Tuberous sclerosis Ataxia telangiectasia Gaucher syndrome Peutz-Jeger
Others: Proteus, Hunter, Ring chromosome, Chediak Higashi, Maffucci, Watson, Turner etc.
What’s LAMB syndrome?
Carney complex MEN syndrome Lentigines of face and vulva Atrial myxoma Mucocutaneous myxomas Blue nevus
What is LEOPARD syndrome?
AD Generalised lentigines ECG abnormalities Ocular hypertelorism Pulmonary stenosis Abnormal genitals (cryptorchidism, ypogonadism, hypospadius) Growth Retardation Deafness (sensorineural)
Others: HOCM, Pectus excavatum/carinatum.
How many cafe au lait spots can you have to be normal?
1-3.
What is the crowe sign?
axillary freckling in NF-1
What conditions give you albinism?
Oculocutaneous albinism Hermansky-Pudlak Chediak-Higashi Piebaldism Waardenburg.
What is the most common form of albinism in the world?
OCA2
VA and nystagmus improve with age.
Prader-Willi and Angelman have dletions including the gene in OCA2
Where is the gene defect in OCA1?
Tyrosinase
What are complications of albinism?
Prone to actinic keratoses and cutaneous carcinomas (absence of normal protection of melanin)
What is chediak higashi syndrome?
Dysfunction of lysosome related organelles.
Hypopigmentation of skin, eyes, hair
Prolonged bleeding times and easy bruising
Recurrent infections
Abnoraml NK cell function
Periphearl neuropathy.
What are hypomelanosis of Ito?
Present at birth. Hypopigmented macules in whirls that follow line of blaschko (sparing palms, soles, mucous membranes) Associated with 1. Mental retardation (70%) 2. Seizures (40%) 3. Microcephaly (25%) 4. Muscular hypotonia (15%)
What conditions are seen with vitiligo?
TS Addison disease Hashimoto Perniciious anemia DM Hypoparathyroidism IgA deficiency Alopecia
What is the most common cause of erythema multiforme?
HSV
What is the classic erythema multiforme lesion?
Doughnut shaped, target like papuleswith erythematous outer border, pale inner ring and purple centre.
Usually on extensor upper extremeties. Happen 10-14 days after HSV.
What infectious cause can lead to stevens-johnson syndrome?
Mycoplasma pneumoniae.
How do you diagnose Stevens Johnson dynrome?
Erythematous macules, then develop central necrosis. More widespread than EM and involve 2 OR MORE MUCOSAL SURFACES.
Leisons may be preceded by viral illness
What is the pathogenesis of SJS?
Related to drug-specific CD8 T cells with perforin/granzyme Ba nd granulysin trigegering keratinocyte apoptosis.