Dermatology Flashcards
What is aplasia cutis congenita?
Isolated defect where a portion of skin is missing
Where does aplasia cutis congenita most frequently occur?
Posterior scalp
Which conditions is aplasia cutis congenita associated with?
Epidermolysis bullosa Limb defects Spinal dysraphism T13 Goltz syndrome Adams-Oliver syndrome
What are the features of Kasabach-Merritt syndrome?
Thrombocytopenia
Rapidly enlarging haemangioma
Microangiopathic haemolytic anaemia
Localised consumption coagulopathy
What are the features of PHACES syndrome?
Posterior fossa defects
Haemangiomas (usually large facial ones)
Arterial anomalies
Cardiac defects and coarctation of the aorta
Eye anomalies
Sternal clefting and/or supraumbilical raphe
What are the three broad types of epidermolysis bulls?
EB simplex
Junctional EB
Dystrophic EB
How is EB simplex inherited?
Autosomal dominant (mainly)
What is the defect in EB simplex?
Defect in basal layer of epidermis, affecting keratins 5-14
How does EB simplex present?
Blisters at friction sites, often when child starts to crawl or walk
Hair, teeth and nails not affected
How is junctional EB inherited?
Autosomal recessive?
How serious is junctional EB?
There are Lethal and non-lethal variants
What is the defect in junctional EB?
Laminin-5
What are the features of junctional EB?
Mucous membranes can be severely affected
Teeth often abnormal
Raw, denuded areas show little tendency to heal
Hoarseness as a result of laryngeal involvement
How is dystrophic EB inherited?
Autosomal dominant or recessive
What is the defect in dystrophic EB?
Collagen VII
What are the features of dystrophic EB?
Subepidermal blister
Lesions heal with scarring
Hair and teeth are normal in dominant form
Mucous membranes, nailed, hair and teeth may all be abnormal in recessive form
Web formation between digits leads to a useless fist
What is one of the possible sequelae of dystrophic EB?
Squamous carcinoma
When does chronic bullous dermatosis of childhood usually present?
> 3 years, mean age 5 years
How does chronic bullous dermatosis of childhood present?
Tense blisters like a string of pearls, usually on abdomen and buttocks
Can present as genital blisters/erosions
40% have mucous membrane involvement
Clears after 3 years
Which antibody is positive in chronic bullous dermatosis of childhood?
Linear basement membrane IgA
When does dermatitis herpetiformis usually present?
Mean age 7 years
How does dermatitis herpetiformis present?
Buttocks, elbows, back of neck and scalp
Itchy
15% resolve spontaneously
Skin changes can persist up to 18 months after starting gluten free diet
Which antibody will be positive in dermatitis herpetiformis?
IgA in papillary dermis
How does epidermolysis bullosa acquisita present?
Mechanobullous picture with blisters localised to areas of traum
What is the prognosis for epidermolysis bullosa acquisita?
Remits in 2-4 years
Which antibody will be positive in epidermolysis bullosa acquisita?
Linear basement membrane IgG
What are the features of pemphigus?
Flaccid blisters
Nikolsky sign positive
Mucous membrane involvement in vulgaris type with stomatitis
What is the Nikolsky sign?
Blister induced by rubbing normal appearing skin
Which antibody will be positive in pemphigus?
Intercellular IgG
What are the dermatological features of PKU?
Decreased pigmentation: fair hair, lightly pigmented eyes
Eczema
How is xeroderma pigmentosum inherited?
Autosomal recessive
What is the defect in xeroderma pigmentosum?
DNA repair defect
What are the clinical features of xeroderma pigmentosum?
Extreme photosensitivity Severe ophthalmological abnormalities Skin malignancies in childhood Neurological complications in 20% Freckling
How is Cockayne syndrome inherited?
Autosomal recessive
What is the basic problem in Cockayne syndrome?
Cells have increased sensitivity to UV light
When does Cockayne syndrome present?
2nd year of life
What are the clinical features of Cockayne syndrome?
Progressive neurological degeneration and growth failure Sensorineural hearing loss Skeletal abnormalities Dental caries Pigmentary retinopathy Cataracts
How is trichothiodystrophy inherited?
Autosomal recessive
What are the features of trichothiodystrophy?
Photosensitivity Ichthyosis Brittle, low sulphur hair Intellectual impairment Decreased fertility Short stature
How is Rothmund-Thomson syndrome inherited?
Autosomal recessive
What are the features of Rothmund-Thomson syndrome?
Poikiloderma (atrophic pigmented telangiectasia) by end of 1st year Sparse hair Skeletal dysplasia Short stature Cataracts Hypogonadism Hypotrophic nails Increased risk of osteosarcoma and skin malignancy
How is Bloom syndrome inherited?
Autosomal recessive
What are the features of Bloom syndrome?
Growth retardation Immunodeficiency (IgA and IgM) Telangiectasia Pigmentary abnormalities Malignancies in 3rd decade (leukaemia, lymphoma)
How is Hartnup disease inherited?
Autosomal recessive
What is the defect in Hartnup disease?
Impaired amino acid transport in kidneys and small intestine
What are the symptoms of Hartnup disease?
Can be asymptomatic Photosensitivity with pellagra-like appearance Can form blisters Intermittent cerebellar ataxia Psychotic behaviour Mild learning disability
What are the porphyria?
Group of disorders leading to accumulation of haem precursors
What skin problems are elevated porphyrins associated with?
Acute photosensitivity or skin fragility with vesiculobullous and erosive lesions
What is the most common porphyria in children?
Erythropoietic protoporphyria
How is Erythropoietic protoporphyria inherited?
Usually autosomal dominan
What are the features of Erythropoietic protoporphyria?
Small pitted scars on nose and cheeks
Burning/stinging in exposed skin
Photosensitivity less severe in adult life
Gallstones in childhood
What test results will be seen. in Erythropoietic protoporphyria?
Excess protoporphyrins in red cells and faeces; urine normal
How is congenital erythropoietic porphyria inherited?
Autosomal recessive
When does congenital erythropoietic porphyria present?
Shortly after birth
What are the features of congenital erythropoietic porphyria?
Acute episodes become less severe with time, leaving scarring, ulceration and deformity Sclerodactyly Loss of terminal phalanges Severe photosensitivity Red staining of nappy Haemolytic anaemia and splenomegaly Hypertrichosis Teeth and bones may be red
What causes porphyria cutanea tarda?
Familial or provoked by drugs, alcohol, or infection
What are the features of porphyria cutanea tarda?
Skin fragility leading to vesicles/blisters and erosions Hypertrichosis Yellow/blue nails and onycholysis Anorexia constipation, diarrhoea Dark brown urine
What are ichthyoses?
Disorders of keratinisation, characterised by excessively dry and visibly scaly skin
How is Sjogren-Larsson syndrome inherited?
Autosomal recessive
What are the features of Sjogren-Larsson syndrome?
Spastic diplegia or tetraplegia
Learning disability
Ichthyosis
Onset of neurological signs at 4-13 months of age
What is the defect in Sjogren-Larsson syndrome?
Fatty alcohol oxidation defect in fibroblasts
How is Refsum disease inherited?
Autosomal recessive
What is the defect in Refsum disease?
Phytanic acid oxidase defect
What are the features of Refsum disease?
Retinitis pigmentosa Peripheral neuropathy Anosma Sensorineural deafness Variable ichthyosis: vulgars-type appearance with fine, light scaling
What is associated steroid sulphatase deficiency?
X-linked recessive ichthyosis
What can associated steroid sulphatase deficiency be associated with?
Kallmann syndrome Pyloric stenosis Chondroplasia punctata Hypogonadism Learning disability
How is multiple sulphatase deficiency inherited?
Autosomal recessive
What is the defect in multiple sulphatase deficiency?
Lack of arylsulphatase A, B and steroid sulphatase
What are the features of multiple sulphatase deficiency?
Ichthyosis Neurodegenerative disease Coarse facies Hepatosplenomegaly Lumbar kyphosis
How is Netherton syndrome inherited?
Autosomal recessive
What are the features of Netherton syndrome?
Neonatal erythroderma Ichthyosis liners circumflex Atopy Faltering growth Recurrent infections Trichorrhosis invaginata
How is Happle syndrome inherited?
X-linked dominant
What are the features of Happle syndrome?
Chondroplasia punctata Cicatricial alopecia Cataracts Short stature Follicular atrophoderma
What are the features of KID syndrome?
Keratitis
Ichthyosis
Deafness
How is KID syndrome inherited?
Unclear
How is Chanarin-Dorfman syndrome inherited?
Autosomal recessive
What is the defect in Chanarin-Dorfman syndrome?
Neutral-lipid storage disease
What are the features of Chanarin-Dorfman syndrome?
Variable neurological and ocular involvement
Multiple lipid vacuoles in monocytes and granulocytes
Ichthyosis
What are the features of CHILD syndrome?
Congenital hemidysplasia
Ichthyosiform erythroderma
Limb defects
How is Chediak-Higashi syndrome inherited?
Autosomal recessive
What are the features of Chediak-Higashi syndrome?
Incomplete oculocutaneous albinism
Photophobia
Severe recurrent infections
What are the dermatological features of Niemann-Pick type A?
Grey-brown/yellow-brown discolouration of sun exposed areas
What is koilonychia a sign of?
Iron deficiency anaemia
What is leukonychia a sign of?
Liver disease
Hypoalbuminaemia
Hereditary
If punctate, can follow minor trauma
How is nail-patella syndrome inherited?
Autosomal dominant
What are the features of nail-patella syndrome?
Nail hypoplasia Patella hypoplastic or absent Radial head abnormalities Iliac crest exostosis Nephropathy
