Skin signs in systemic disease Flashcards
(40 cards)
What is tuberous sclerosis?
It is a rare genetic condition that causes many benign tumours to grow in different parts of the body - skin, brain, kidneys, heart, eyes and lungs. It is present from birth but may not manifest until later in life
What genetic mutation occurs in tuberous sclerosis?
Tuberous sclerosis is caused by changes (mutations) in either the TSC1 or TSC2 gene. These genes are involved in regulating cell growth, and the mutations lead to uncontrolled growth and multiple tumours throughout the body
What skin signs are seen in tuberous sclerosis?
There may be light coloured spots, called hypomelanotic macules, and bumps on the skin of several different types (angiofibroma, cephalic fibrous plaques, shagreen patches, and ungual fibromas)
What is neurofibromatosis?
Neurofibromatosis is a genetic disorder that causes tumours to form on nerve tissue. These tumours can develop anywhere in your nervous system, including your brain, spinal cord and nerves
Is NF-1 autosomal dominant or recessive and what chromosome is the mutation on?
It is autosomal dominant and the mutation is on chromosome 17
What common signs are seen in NF-1?
Café au lait Neurofibromas Plexiform neuroma - diffuse Axillary or inguinal freckling Optic glioma 2 or more Lisch nodules A distinctive bony lesion
What kind of inheritance is NF-2 and what chromosome is the mutation on?
Autosomal dominant and chromosome 22 (on a gene that encodes for the merlin protein)
What are the common features of NF-2?
Bilateral vestibular schwannoma!!!! Multiple meningiomas Gliomas Café au lait Neurofibromas Cataracts
Incontinentia pigmenti and Peutz Jegher’s syndrome are also genetic conditions with skin manifestations
Look into but probably don’t need to know in depth
What skin signs of diabetes are there?
Infection Ulcers Xanthomata Necrobiosis Lipoidica Acanthosis Nigricans Granuloma Annulare (rare) Diabetic dermopathy - brown atrophic lesions on legs Perforating disorders, bullae formation
What pathological processes are thought to be involved in the skin signs seen in diabetes?
Glycosylation of collagen and other proteins
Small and large vessel angiopathy
Loss of sensory nerve function
Abnormal lipid metabolism
Hyperinsulinaemia activating IGF receptors
Erysipelas and candidiasis are commonly seen infections in diabetics. What is erysipelas? What bacteria causes it?
It is a bacterial infection of the upper layers of the skin. It is similar in appearance to cellulitis but cellulitis affects deeper layers. It is caused by beta haemolytic group A strep bacterium
What are the signs and symptoms of erysipelas and how is it treated?
fever chills generally feeling unwell a red, swollen, and painful area of skin with a raised edge blisters on the affected area swollen glands
Treatment - elevate area affected, antibiotics (flucloxacillin likely choice)
What are Xanthomata?
Deposits of cholesterol on skin
What is necrobiosis lipoidica?
Necrobiosis lipoidica is an uncommon inflammatory condition in which shiny, red-brown or yellowish patches develop in the skin, usually in young adults and in early middle age and usually over the shins. The condition is most commonly seen in conjunction with diabetes. Only one in three hundred diabetics have necrobiosis lipoidica, but most patients with necrobiosis lipoidica have, or will develop, diabetes
What is acanthosis nigricans?
Acanthosis nigricans is a skin condition characterized by areas of dark, velvety discoloration in body folds and creases. The affected skin can become thickened. Most often, acanthosis nigricans affects your armpits, groin and neck
Skin changes seen in hyperthyroidism?
Warm, moist smooth skin Facial flushing and palmar erythema Fine, thin hair, diffuse alopecia Increased sweating (hyperhidrosis) Pruritus Graves - pretibial myxoedema
Skin changes seen in hypothyroidism?
Cold, dry pale skin
Xerosis (dry skin)
Carotenaemia - yellowing of the skin (xanthoderma)
Dry, coarse, brittle hair, diffuse alopecia
Loss of lateral 1/3rd of the eyebrow
Thickened, brittle nails
Generalised myxoedema which disappears with correction of T4 levels
What skin changes are seen in Addison’s disease?
NB. It is a primary adrenocortical insufficiency
Diffuse hyperpigmentation
Palmar crease pigmentation
Buccal pigmentation
Absence of normal glucocorticoid feedback to pituitary gland leads to increased ACTH and MSH (melanostimulating hormone) production leading to increased melanogenesis
What tumours have MSH-like affect and what tumour has androgenic activity?
MSH-like = Lung and pituitary tumours - leads to hyperpigmentation
Androgenic activity = Ovarian tumours - leads to hirsutism, acne, baldness, and virilisation
Lupus erythematosus covers a spectrum of presentation:
Chronic or acute discoid lupus erythematosus
Subacute cutaneous LE
Systemic LE
How does CDLE present and how can it be diagnosed?
Photosensitivity
Erythematous indurated plaques on exposed sites
Follicular plugging
Heal with scarring/permanent alopecia
Dx - Biopsy and IMF
May be ANA+
How is discoid LE treated?
Sun avoidance
Potent/ v.potent steroids
Oral antimalarials
How does subacute cutaneous lupus erythematosus present?
Usually annular erythematous scaly plaques, not indurated. Symmetrical
Photosensitive
Mainly on sun-exposed sites - upper back, shoulders, arms
Heal without scarring
Systemic disease is common
What are the skin features of systemic LE?
F:M 7:1 Butterfly skin rash UV sensitivity Dilated, tortuous nail-fold capillaries May have widespread discoid LE type rash
