Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Y2 Dermatology > Week 1.5 > Flashcards

Week 1.5 Flashcards

1
Q

What are the 2 stages in all hypersensitivity reactions

A

Sensitisation stage
Effector stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Features of type 1 hypersensitivity reaction

A

Immediate reaction - symptoms onset minutes up to Hours
IgE mediated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mechanism of type 1 hypersensitivity reaction

A
  1. On first exposure to allergen, B cells produce IgE antibodies
  2. Some remaining IgE antibodies bind to Fc receptors of mast cells
  3. Mast cells circulate the blood stream
  4. On re-exposure to the allergen, the antigen binds onto IgE on mast cells causing mast cells to degranulate
  5. Mast cells release histamine and inflammatory cytokines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Common allergens causing type 1 hypersensitivity

A

Pollen
Food
Animals
Drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Symptoms that can be caused by type 1 hypersensitivity

A

Urticaria - very itchy lesions that look like hives
Angioedema
Anaphylaxis (if severe reaction)
Asthma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Symptoms of anaphylaxis

A

Laryngeal / pharyngeal oedema
Bronchospasm
tachypnea
Hypotension
Tachycardia
Urticaria
Allergic rhinitis / conjunctivitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Investigations for type 1 hypersensitivity

A

History
Skin prick test
Challenge test if skin prick test is negative but history strongly suggests so

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

First line treatment for type 1 hypersensitivity

A

Avoid allergen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Management for acute T1 hypersensitivity attack

A
  1. Anti-histamines
  2. Corticosteroids
  3. Epi pen (adrenaline pen) if anaphylaxis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Examples of anti-histamines

A

Chlorphenamine
Diphenhydramine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Examples of corticosteroids used in type 1 hypersensitivity

A

Prednisolone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Features of type 2 hypersensitivity

A

Takes hours - days for reaction after exposure
IgG and IgM mediated
Cytotoxic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does IgG and IgM cause cytotoxic reaction in type 2 hypersensitivity

A

Activation of complement system
Antibody dependent cell mediated cytotoxicity (ADCC)
Opsonization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the antibody-dependent cell mediated cytotoxicity in type 2 hypersensitivity

A
  1. IgG/IgM binds to antigens
    2 Natural killer cells bind to the Fc portion of IgM/IgG antigen complexes
  2. NK cells causes cell death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Examples of conditions due to Type 2 hypersensitivity

A

Haemolytic anaemia
Goodpasture’s syndrome
Grave’s disease
Bullous pemphigoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Goodpasture’s syndrome

A

When the IgG and IgM antibodies are directed to attack a specific collagen found in basement membrane of alveoli and glomeruli
Causes lungs and kidney damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Presentation of Goodpasture’s syndrome

A

Haemoptysis
SOB
Renal dysfunction - decreased urine output
Renal failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Features of type 3 hypersensitivity

A

Takes hours - days for reaction to occur after exposure
Antigen-antibody immune complex mediated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Difference between type 2 and type 3 hypersensitivity

A

In type 3, the antibodies are bound to soluble antigens unlike in type 2 where IgG and IgM are bound to antigens on cells
In type 3, it triggers inflammation cascade in certain areas instead of cytotoxicity in type 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Mechanism of type 3 hypersensitivity

A
  1. sensitisation
  2. effector stage: Antibody covers the soluble antigen forming antibody-antigen complexes. The complexes can move and deposit in certain areas and trigger inflammation there
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The immune complexes in type 3 hypersensitivity often deposit in

A

Blood vessels
Synovial joints
Glomerular basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Examples of conditions due to type 3 hypersensitivity

A

Rheumatoid arthritis
SLE
Post streptococcal glomerulonephritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Features of type 4 hypersensitivity

A

Takes days for reaction to occur after exposure
T cell mediated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why is type 4 hypersensitivity called delayed hypersensitivity

A

Because it takes time for T cells to recruit to sites where antigen is at hence causes delayed response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Examples of conditions due to type 4 hypersensitivity
Contact dermatitis Drug eruptions - exanthematous and fixed drug eruptions
26
What are drug eruptions
Symmetrical skin eruption due to certain medications and this skin eruption resolves after withdrawal of the medication
27
The amount of time drug eruptions take to resolve depends on
the half life of the drug
28
Different types of drug eruptions (depending on presentation)
Exanthematous drug eruption Urticarial drug eruption Bullous or pustular drug eruption Fixed drug eruption
29
Risk factors for drug eruptions
Elderly, young adults Females Genetics HIV / EBV / CMV / cystic fibrosis Drugs that have higher risk of causing drug eruptions
30
What are the drugs that have higher risk of causing drug eruptions
Beta lactam antibiotics NSAID Anti-epilepsy drugs Topical drugs
31
Which type of drug eruption is the most common
Exanthematous drug eruption
32
Exanthematous drug eruption is due to which type of hypersensitivity
Type 4
33
Onset of symptoms of exanthematous drug eruptions
4 - 21 days May appear within 1-3 days on re-exposure to the drug
34
What are the drugs that commonly causes exanthematous drug eruption
Penicillin (beta lactam antibiotics) Carbamezapine and phenytoin Allopurinol Erythromycin Streptomycin NSAID
35
What type of drugs are carbamezapine and phenytoin
Anti-epileptic drugs
36
What is allopurinol used for
To treat gout attacks
37
Symptoms of mild - moderate exanthematous drug eruption
Widespread bilateral symmetrical macules and papule Pruritus Mild fever
38
Which parts of the body is often spared in exathematous drug eruption
Mucous membranes Axilla groin hands feet
39
What are the symptoms of severe exanthematous drug eruption
High fever Involvement of mucous membranes Widespread oedema and erythema Blisters / necrosis Skin pain Dyspnea
40
Which type of hypersensitivity causes urticarial drug eruptions
Type 1
41
Urticarial drug eruptions can occur on first exposure as well. Why
Due to pseudo-allergic reaction which is not dependent on the immune system (not IgE dependent)
42
What is pseudo allergic reaction
When it causes direct release of histamine and cytokines from mast cells without needing IgE to bind to Fc receptors of mast cells first
43
Onset of symptoms in urticarial drug eruptions due to type 1 hypersensitivity
Immediate reaction
44
Drugs that causes urticarial reaction due to type 1 hypersensitivity
Beta lactam antibiotics Carbamezapine, phenytoin (anti-epileptics
45
Examples of beta lactam antibiotics
Penicillins - amoxicillin, penicillin Cephalosporin - cephalexin, ceftriazone
46
Drugs that can cause urticarial reaction due to pseudo allergic reaction
Opiates NSAID Aspirin Vancomycin
47
Symptoms of urticarial drug eruptions
Pruritic red hives rash Angio-oedema
48
What are the subtypes of bullous / pustular drug eruptions
Acneiform Acute generalised exanthematous pustulosis Drug induced bullous pemphigoid Linear IgA disease
49
What is Acneiform
Pus filled, red, acne like bumps but are not acne
50
How to differentiate between acneiform drug eruption and acne
Acneiform resolves with discontinuation of drug Acneiform has an acute onset
51
Drugs that causes aceniform eruption
Steroids Androgens Lithium Isoniazid
52
What is isoniazid used for
treat TB
53
Onset of symptoms for acute generalised exanthematous pustulosis is
within 2 days of exposure
54
Drugs that causes acute generalised exanthematous pustulosis
Beta lactam antibiotics CCB Tetracyclines Hydroxycloroquine Carbamazepine Paracetamol
55
What is hydroxycloroquine used for
It is a DMARD, used for rheumatoid arthritis It is also used to treat malaria
56
Symptoms of acute generalised exanthematous pustulosis
Widespread rash Many small, non-follicular, sterile pustules
57
What are non-follicular pustules
The inflammatory infiltrate does not accumulate in hair follicles
58
What is a sterile pustule
Bacterial culture obtained from the pustular fluids is negative
59
Symptoms of drug induced bullous pemphigoid
Itchy large bullae Eruptions of bullae causes crusted erosions
60
Drugs that causes drug induced bullous pemphigoid
PD1 inhibitor immunotherapies ACEi Penicillin Furosemide DPP4
61
What is linear IgA disease
Linear deposits of IgA at basement membrane causing bullae
62
Which drug can trigger linear IgA disease
Vancomycin
63
What is fixed drug eruption
Reaction that recurs at the same site on re-exposure to the medication
64
Which type of hypersensitivity causes fixed drug eruption
Type 4
65
What drugs causes fixed drug eruption
NSAID Paracetamol Tetracycline Sulfonamides
66
Type of rash caused by fixed drug eruption
Well demarcated round plaques Red Painful Persistent pigmentation even after stopping the drug May occur as bullous / on mucous membranes
67
Which mucous membranes can be affected by fixed drug eruption
Lips Tongue Genitals
68
What is Stevens-Johnson Syndrome (SJS)
Dermatological emergency most commonly caused by severe drug reactions but can also be caused by viral infections
69
What is Toxic epidermal necrolysis
The most severe form of Stevens-Johnson Syndrome
70
Drugs that can cause SJS
Sulfonamides Beta lactam antibiotics NSAID Anti-epileptics - carbamezapine and phenytoin Allopurinol
71
Viral infections that can cause SJS
Herpes Simplex EBV HIV Influenza Hepatitis
72
When do symptoms of SJS usually present
within a week of taking a medication
73
Symptoms of SJS
Mucosal ulceration of at least 2 mucosal membranes Erythematous macules that become target shaped Flaccid blisters Systemically unwell
74
What are the mucosal membranes that can be affected by SJS
Mouth Conjunctiva Urethra Pharynx GI tract
75
What is a target lesion
Round lesion with 3 colour zones: - darker center - raised pale pink ring around the center - bright red outermost ring
76
Investigations for SJS
Nikolsky sign Skin biopsy
77
What is Nikolsky sign
When slightly rubbing the roof of the lesion using eraser part of the pencil causes the lesion to open
78
How does SJS lead to death
Due to damage to the skin barrier = the skin loses its function - dehydration - infection - hypothermia - disseminated intravascular coagulation
79
What is disseminated intravascular coagulation
Coagulation pathway becomes overreactive causing formation of blood clots
80
Management of SJS
Supportive - pain relief, antibiotics if there is infection Ophthalmology referral
81
What is drug phototoxicity
Non-immunological skin reaction due to light activation of a photo-reactive drug
82
Which UV light most commonly causes drug phototoxicity
UVA
83
Common phototoxic drugs
NSAID CCB Thiazide diuretics Amiodarone Tetracycline Quinine Chlorpromazine
84
What is quinine used for
Malaria Leg cramps
85
What is chlorpromazine used for
Psychosis, anxiety, mania
86
What are the skin reactions due to phototoxicity
Exaggerated sunburn Pseudoporphyria Exposed telangiectasia Delayed erythema and pigmentation Immediate prickling with delayed erythema and pigmentation
87
What is psuedoporphyria
Bullous photodermatosis with features of porphyria cutanea tarda but without any abnormalities in porphyrin metabolism
88
What is porphyrin cutanea tarda
Painful blisters that develop when you become exposed to the sun
89
What causes porphyrin cutanea tarda
Deficiency in UROD enzyme (uroporphyrinogen decarboxylase) which is needed to break down porphyrin. Build up of porphyrin causes porphyrin to absorb sunlight and become activated and causes damage to skin
90
Which drugs cause exaggerated sunburn due to phototoxicity
Thiazides Quinine Tetracycline
91
Which drug causes pseudoporphyria due to phototoxicity
NSAID
92
Which drug causes telangiectasia on sun exposed sites due to phototoxicity
CCB
93
Which drugs cause delayed erythema and pigmentation due to phototoxicity
Psoralen
94
When is psoralen used
PUVA (phototherapy) for psoriasis
95
Which drug causes immediate prickling with delayed erythema and pigmentation due to phototoxicity
Amiodarone Chlorpromazine
96
Management of phototoxicity
Discontinue the drug and use alternative Topical steroids

Y2 Dermatology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions