Dermatology - Autoimmune Disorders Flashcards
What is vitiligo?
An autoimmune dermatological condition in which there is loss of melanocytes in the epidermis, resulting in a loss of pigmentation.
Give some autoimmune diseases associated with vitiligo
- Addison’s disease
- Thyroid disease
- T1 diabetes
- Polyendocrine genetic conditions
- Rheumatoid arthritis
- Myasthenia gravis
- Pernicious anaemia
- Autoimmune hepatitis
- Alopecia areata
- Psoriasis
- Lichen planus
- Lichen noticeable
Describe the lesions in vitiligo
- Well-demarcated
- Smooth, flat patches of depigmentation
The lesions in vitiligo may be segmental or non-segmental. What is the different?
Segmental:
- Unilateral, following one or more dermatomes
- Tends to affect children
- Rapid onset
- Not accompanied by other autoimmune disease
Non-segmental:
- Localised or generalised
- Tends to affect adults
- Is progressive with noticeable ‘flares’
- More often associated with other autoimmune disease
Does segmental vitiligo tend to be associated with children or adults?
Children
What is the Koebner phenomenon?
The appearance of new skin lesions of a pre-existing dermatosis on areas of cutaneous injury in otherwise healthy skin.
Location of lesions in vitiligo?
Common in areas of increased friction (Koebner phenomenon) i.e. fingers, beneath watch strap, genitals
How does body hair appear in areas of vitiligo?
White
Management of vitiligo?
- Strongly advise wearing sunscreen
- Topical steroid cream may induce re-pigmentation
- UVB or PUVA treatment in those with widespread disease and psychological impact
What is alopecia areata?
Describes loss of hair from areas where hair normally grows.
What are the 2 types of alopecia?
- Scarring
- Non-scarring
What happens in scarring alopecia?
- Hair follicles destroyed
- Skin becomes scarred
Is scarring alopecia reversible?
No
What happens in non-scarring alopecia?
- Hair follicles NOT destroyed
- Skin does NOT scar
Is scarring or non-scarring alopecia more common?
Non scarring
Is non-scarring alopecia reversible?
Yes
Is alopecia areata a type of scarring or non-scarring alopecia?
Non-scarring
Pathophysiology of alopecia areata?
Autoimmune
Presentation of alopecia areata?
- Well-defined patches of hair loss
- Surrounding hairs are narrower near base – ‘exclamation mark’ hairs
- Usually reverses spontaneously after a few months
What are exclamation mark hairs?
Exclamation point hairs are short, broken hairs that can be extracted with minimal traction and where the proximal end of the hair is narrower than the distal end.
Management of alopecia areata?
- No reliable cure
- Topical steroids
What is SLE?
Systemic lupus erythematosus (SLE) is an autoimmune disease that causes inflammation in connective tissues (e.g. cartilage, lining of blood vessels).
Pathophysiology of SLE?
Immune complex deposition
What are the 3 different forms of cutaneous lupus?
- Acute cutaneous LE
- Subacute cutaneous LE
- Chronic cutaneous LE
Who does acute cutaneous LE affect?
People with active disease
What is the characteristic cutaneous feature of acute cutaneous LE?
- Malar rash (butterfly rash) → erythema of the malar eminences and across the bridge of the nose, classically the nasolabial folds are spared
- Photosensitivity
Define malar
Involving the cheeks
Describe the presentation of subacute cutaneous LE
Results in widespread, psoriasis-like papulosquamous rash or annular plaques with clear centre
What is the commonest type of cutaneous lupus?
Chronic cutaneous LE
Who does chronic cutaneous LE affect?
Affects people without active disease
Describe the presentation of chronic cutaneous LE
- Discoid, erythematous scaly plaques
- Scarring and atrophy occur later
What is dermatomyositis?
A rare condition that consists of skin signs and myositis.
What is myositis?
Myositis is the name for a group of rare conditions that can cause muscles to become weak, tired and painful. The word myositis simply means inflammation in muscles.
Describe the muscle presentation of dermatomyositis
- Proximal muscle weakness and myalgia
- Difficulty rising from a chair, climbing stairs, lifting objects and raising arms (e.g. to comb hair)
Are the proximal or distal muscles affected in dermatomyositis?
Proximal
Describe the skin signs in detmatomyositis
- Helicotrope rash
- Gottron’s papules
- Shawl rash
- Nailfold erythema
What is a helicotrope rash?
A heliotrope rash is a reddish purple rash on or around the eyelids.
What is a shawl rash?
erythema across the upper back and shoulders
What are Gottron’s papules?
red papules on dorsal aspect of finger joints
What is the diagnostic investigation in dermatomyositis?
A muscle biopsy
What may an autoantibody screen show in dermatomyositis?
May show anti-Mi2 and anti-Jo1 antibodies
What bloods may be useful in dermatomyositis?
Plasma muscles enzymes (CK, ALT, AST, LDH)
What is the 1st line management of dermatomyositis?
Oral corticosteroids
What should you always screen for in dermatomyositis?
Screen for malignancy!!! Dermatomyositis can be a para-neoplastic phenomenon
What is vasculitis?
A group of autoimmune disorders in which there are inflamed blood vessels in the skin
How are vasculitis classified?
Categorised based on whether they affect small, medium or large vessels.
What types of vasculitis affect small vessels?
- Henoch-Schonlein purpura
- Eosinophilic Granulomatous with Polyangiitis (Churg-Strauss syndrome)
- Microscopic polyangiitis
- Granulomatosis with polyangiitis (Wegener’s granulomatosis)
What types of vasculitis affect medium vessels?
- Polyarteritis nodosa
- Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss syndrome)
- Kawasaki disease
What types of vasculitis affect large vessels?
- Giant cell arteritis
- Takayasu’s arteritis
Give some general clinical features that apply to most types of vasculitis
- Purpura
- Joint muscle & pain
- Peripheral neuropathy
- Renal impairment
- GI disturbance (diarrhoea, abdo pain, bleeding)
- Anterior uveitis and scleritis
- Hypertension
- Systemic manifestations - fever, fatigue, weight loss, anaemia
What is the classic dermatological feature of vasculitis
Purpura - purple-coloured non-blanching spots caused by blood leaking into the skin
Which autoantibody indicates vasculitis?
ANCA (anti-neutrophil cystoplasmic antibodies)
What are the 2 types of ANCA? What does each indicate?
- p-ANCA (also called anti-MPO) → microscopic polyangiitis, Churg-Strauss syndrome
- c-ANCA (also called anti-PR3) → Wegener’s granulomatosis
Pharmacological management of vasculitis?
Involves a combination of steroids and immunosuppressants.
- Steroids:
- Oral (prednisolone)
- IV (i.e. hydrocortisone)
- Nasal sprays for nasal symptoms
- Inhaled for lung involvement (e.g. Churg-Strauss syndrome)
- Immunosuppressants:
- Cyclophosphamide
- Methotrexate
- Azathioprine
- Rituximab and other monoclonal Abs
What is Henoch-Schonlein Purpura?
Small vessel vasculitis
What is the most common vasculitis seen in children aged 3-15?
Henoch-Schonlein Purpura
Pathophysiology of Henoch-Schonlein Purpura?
Small vessel leukocytoclastic vasculitis involving the deposition of IgA immune complexes in affected organs
What is Henoch-Schonlein Purpura thought to be triggered by?
A viral URTI
What tetrad of symptoms does Henoch-Schönlein purpura (HSP) usually present with?
- Purpuric rash (over extensor surfaces of lower limb)
- Arthralgia/arthritis
- Abdominal pain
- Renal disease (IgA nephritis)
Investigations for Henoch-Schonlein Purpura?
- Urinalysis → presence of blood/protein (renal involvement)
- BP (can be elevated in nephritic syndrome)
Management of HSP?
- Most cases resolve spontaneously and treatment not required
- Symptomatic treatment
- Monitor for signs of renal disease
- Renal involvement → treat with corticosteroids
What is Granulomatosis with Polyangiitis (Wegener’s Granulomatosis)?
Small vessel vasculitis that affects the respiratory tract and kidneys.
Granulomatosis with Polyangiitis commonly affects the nose. How does it present?
- Nose bleeds (epistaxis) and crust nasal secretions
- A classic sign in exams is the saddle shaped nose due to a perforated nasal septum which causes a dip halfway down the nose
What is kawasaki disease?
Kawasaki disease is an acute systemic vasculitis that affects young children.
Classic symptom of Kawasaki disease?
Strawberry tongue
