Itch & Urticaria Flashcards
(105 cards)
1
Q
What is pruritis?
A
A usually unpleasant sensation that elicits the desire to scratch as a strategy to remove exogenous influences like parasites or insects.
2
Q
In what percentage of patients can pruritis indicate an underlying systemic disease?
A
10-25% of patients.
3
Q
Name the three patient groups with different classification of pruritis.
A
- Group 1: pruritis on diseased skin
- Group 2: pruritis on non-diseased skin
- Group 3: chronic scratch lesions
4
Q
What are the categories of disease associated with pruritis?
A
- Dermatologic
- Systemic
- Neurologic
- Psychogenic
- Mixed
- Other
5
Q
What is the pathogenesis of pruritis?
A
Complex and not fully understood.
6
Q
List key questions to ask during history taking for evaluating an itch.
A
- When did it start?
- Any previous episodes?
- Duration?
- Time course?
- Localised or generalised?
- Nature of the sensation?
- Does it interrupt sleep or ADLs?
- Provoking factors?
- Any Rx or supplements?
- Any known allergies?
- Any Hx of atopy?
- Relevant PMHx?
- Any FHx?
- Occupation/hobbies?
- Pets?
- Travel Hx?
- Any previous Dx?
7
Q
True or False: There are specific clinical findings that can reliably predict an underlying systemic disease in itchy patients.
A
False.
8
Q
What should be included in a general physical examination for pruritis?
A
- LNs
- Exam for hepatosplenomegaly
- Skin
- Nails
- Scalp
- Hair
- Mucous membranes
- Anogenital region
9
Q
What are secondary changes in pruritis?
A
- Erosions
- Excoriation
- Crusting
10
Q
What are key features to assess in pruritis?
A
- Lichenification
- Xerosis
- Dermographism
- Other skin signs of systemic disease
11
Q
What are first-line investigations for pruritis?
A
- FBC and blood film
- Iron studies
- Renal function
- LFT
- Thyroid function
- LDH
- Glucose or HbA1c
- ESR and/or CRP
12
Q
Name some dermatological diseases associated with itch.
A
- Scabies
- Atopic dermatitis
- Stasis dermatitis
- Allergic or irritant contact dermatitis
- Psoriasis
- Prurigo nodularis
13
Q
What is a key symptom of atopic dermatitis?
A
Itch is a key symptom and part of the diagnostic criteria.
14
Q
What often triggers itch in atopic dermatitis?
A
A number of immunologic and non-immunologic factors.
15
Q
What describes the itch associated with psoriasis?
A
May be described as tickling, crawling, and burning.
16
Q
What is prurigo nodularis?
A
Raised, nodular lesions produced by repetitive scratching, rubbing, or picking of the skin.
17
Q
What is the role of histamine in urticaria-related itch?
A
Histamine plays a key role in the itch of urticaria.
18
Q
Fill in the blank: The itch associated with urticaria is often described as _______.
A
intense and may be described as stinging or prickling.
19
Q
What are some infections that can cause itch?
A
- Bacterial (e.g., folliculitis)
- Viral (e.g., varicella)
- Fungal (e.g., inflammatory tinea)
- Parasitic (e.g., schistosomal cercarial dermatitis)
20
Q
What are some neoplastic conditions that can be associated with itch?
A
- CTCL (e.g., mycosis fungoides, Sézary syndrome)
21
Q
What treatments are generally not included for CTCL-related itch?
A
Anti-histamines.
22
Q
Name two genetic/naevoid conditions associated with itch.
A
- Darier disease
- Hailey-Hailey disease
23
Q
What are the two main groups of patients with pruritis?
A
- Patients with skin disease
- Patients with other causes
24
Q
What signs of inflammation might patients with skin disease exhibit?
A
- Redness
- Scaling
- Oedema
25
How should pruritis in patients with skin disease be treated?
By treating their skin disease
26
List some other potential systemic causes of pruritis in patients.
* Thyroid disease
* Liver obstruction
* Kidney failure
* Cancer such as lymphoma
27
What skin appearance might patients with pruritis due to non-skin disease causes have?
Normal looking skin or changes from scratching
28
What are the characteristics of skin changes from scratching in pruritis?
* Erosions in a linear array
* Butterfly sign where they can’t reach their back
29
What is the next step after determining a patient has pruritis?
Determine the cause of their itch
30
What should be done if an underlying cause of pruritis is found?
Treat the underlying cause
31
What is often the cause of generalized itches if no underlying cause is found?
Idiopathic
32
How should idiopathic generalized itches be treated?
Symptomatically
33
What is the prevalence of generalized itch in adults?
Approximately 17%
## Footnote
Generalized itch is even more prevalent in the elderly, with rates of 50% or higher.
34
What should be included in the history (Hx) when assessing generalized itch?
Onset, duration, time course, nature of sensation, provoking factors, allergies, medical history, and medications
## Footnote
A thorough medical history is essential for identifying potential causes of itch.
35
What are some dermatological conditions to look for during the examination (Ex) for generalized itch?
Scabies, xerosis, demographic urticaria
## Footnote
Subtle signs of these conditions may be present during the examination.
36
Name some systemic diseases that can cause itch.
* Liver disease
* Renal failure
* Hematological disorders
* Thyroid disease
* Paraneoplastic phenomena
## Footnote
These systemic issues can contribute to generalized itch.
37
What psychological factors should be considered in cases of generalized itch?
Anxiety or depression
## Footnote
These factors can particularly affect older patients, leading to pruritus.
38
What complex disorders may involve dermatological and psychiatric factors?
Delusions of parasitosis, Morgellon's syndrome
## Footnote
These disorders can complicate the diagnosis of generalized itch.
39
What is the diagnosis when no identifiable cause for itch is found?
Idiopathic pruritus
## Footnote
This diagnosis may require prolonged follow-up as the underlying cause may manifest later.
40
True or False: Prolonged follow-up is often unnecessary in cases of idiopathic pruritus.
False
## Footnote
Prolonged follow-up is important as underlying causes may become apparent over time.
41
Fill in the blank: Generalized itch has a prevalence of approximately _____ in the elderly.
50% or higher
## Footnote
This indicates a significant issue in the older population.
42
What is xerosis?
Occurs when skin lacks moisture in the stratum corneum
## Footnote
Xerosis leads to cracks in the skin’s surface.
43
What can cause xerosis?
Environmental factors or systemic diseases such as:
* Hypothyroidism
* Chronic renal disease
* Subclinical dermatitis
## Footnote
These conditions contribute to the lack of moisture in the skin.
44
What are systemic diseases that can cause pruritus?
Systemic diseases causing pruritus include:
* Metabolic diseases (chronic renal failure, liver disease)
* Hematological disorders (anemia)
* Endocrine disorders (thyroid disease, diabetes mellitus)
* Neoplasms (lymphoma, leukemia, solid organ tumors)
## Footnote
Awareness of these conditions is crucial for diagnosis.
45
What should be considered in cases of chronic or generalized pruritus in patients over 65?
An underlying systemic condition
## Footnote
Especially in the absence of primary skin pathology.
46
What are some general measures to manage pruritus?
* Soap-free washing and bathing
* Wet dressings or tepid showers to cool the skin
* Avoidance of precipitating factors
* Keeping nails short and clean to reduce scratching damage
## Footnote
These measures aim to alleviate symptoms and prevent further irritation.
47
What type of emollient should be used at night for pruritus management?
A greasy emollient
## Footnote
Greasy emollients help to retain moisture in the skin overnight.
48
What type of emollient should be used during the day for pruritus management?
An emollient with menthol
## Footnote
Menthol can provide a cooling sensation that helps relieve itch.
49
What are the recommendations for systemic therapy for pruritus?
* Non-sedating antihistamines for up to 4 weeks
* Gabapentin or pregabalin for a minimum of 6 weeks
* Tetracyclic antidepressants (e.g., mirtazapine)
* Selective serotonin reuptake inhibitors (e.g., paroxetine, sertraline, fluoxetine)
## Footnote
These medications may provide relief for severe itch, particularly in specific conditions.
50
True or False: Sedating antihistamines should be used regularly for pruritus management.
False
## Footnote
Sedating antihistamines should only be used intermittently due to the risk of increased dementia.
51
Fill in the blank: Gabapentin or pregabalin may be trialed for a minimum of _____ weeks if the patient tolerates treatment.
6
## Footnote
This duration is suggested to assess the effectiveness of the treatment.
52
Which types of antidepressants may help with severe itch caused by specific conditions?
* Tetracyclic antidepressants (e.g., mirtazapine)
* Selective serotonin reuptake inhibitors (e.g., paroxetine, sertraline, fluoxetine)
## Footnote
These medications may be effective for itch related to cholestasis, T-cell lymphoma, malignancy, or neuropathic cutaneous dysesthesia.
53
What is the first step in the assessment of a patient with pruritus?
Undertake a full history and general examination, including palpation of lymph nodes and abdomen.
## Footnote
This helps in identifying a potential cause of the pruritus.
54
List some potential causes of pruritus.
* Systemic disease
* Medications
* Psychogenic factors
* Aquagenic
* Idiopathic
## Footnote
These causes can vary widely and may require different diagnostic approaches.
55
What does a standard screening for pruritus include?
* Full blood count (FBC)
* Ferritin
* C reactive protein
* Routine biochemistry (urea and electrolytes, creatinine, liver function tests)
* Bone and thyroid function tests
* Antimitochondrial antibody
* Urinalysis
* Chest x-ray
* Baseline lactate dehydrogenase (LDH)
## Footnote
Additional tests may be required based on patient risk factors.
56
What additional tests should be performed for older patients with pruritus?
* Immunoglobulins
* Plasma electrophoresis
* Urine for Bence-Jones protein
## Footnote
These tests help in identifying potential underlying conditions in older patients.
57
What should be considered for patients with new onset severe pruritus?
A CT scan of the neck, chest, abdomen, and pelvis.
## Footnote
This is indicated in the absence of obvious triggers or symptoms.
58
What is a recommended topical agent for pruritus?
1 or 2% menthol in aqueous cream.
## Footnote
It is noted for its cooling properties.
59
What type of antihistamines are recommended for a trial in pruritus?
* Non-sedating antihistamines (e.g., fexofenadine, loratadine)
* Mildly sedating antihistamine (e.g., cetirizine)
## Footnote
A 4-week trial is suggested, with possible dose increases if no improvement is seen.
60
What should be done if there is no significant improvement from antihistamines?
The medication should be stopped.
## Footnote
Non-sedating antihistamines are not supported for use beyond urticaria.
61
What systemic treatments may be trialed for pruritus?
* Gabapentin
* Pregabalin
* Antidepressants (e.g., selective serotonin reuptake inhibitors, mirtazapine)
## Footnote
These treatments may be effective for generalized pruritus.
62
What should be monitored if no underlying cause is found for pruritus?
FBC and LDH levels.
## Footnote
Increasing LDH levels can indicate a late presenting paraneoplastic condition, especially lymphoma.
63
When should a patient be referred to dermatology?
If they are not responding to treatment.
## Footnote
Some patients may respond to phototherapy.
64
What is papular urticaria?
Occurs as a result of insect or arachnid bites
## Footnote
It presents as clusters of papules or fluid-filled blisters, commonly affecting uncovered areas such as the face, arms, and legs.
65
What are the common characteristics of papular urticaria?
Lesions remain for days to weeks and can result in areas of PIH.
## Footnote
PIH stands for post-inflammatory hyperpigmentation.
66
What characterizes urticaria?
Development of itchy wheals (hives)
## Footnote
Urticaria can last from minutes to 24 hours, with or without an area of surrounding erythema.
67
Where can urticaria affect the body?
Can affect any area of the body and tends to be widely distributed.
## Footnote
Urticaria can occur in various forms, including acute or chronic.
68
How is urticaria classified?
According to duration and etiology; it can be acute or chronic, spontaneous or inducible.
## Footnote
Two types can coexist in the same patient.
69
What is mastocytosis?
A wide range of conditions caused by an abnormal growth of mast cells.
## Footnote
These mast cells accumulate in one or more tissues of the body.
70
What is the most common form of mastocytosis?
Maculopapular cutaneous mastocytosis.
## Footnote
It is characterized by areas of skin that become erythematous, swollen, and itchy within minutes of being rubbed (positive Darier sign).
71
What is urticarial vasculitis?
Type of cutaneous small-vessel vasculitis characterized by the development of erythematous wheals.
## Footnote
Urticarial vasculitis lesions typically persist beyond 24 hours.
72
How do urticarial vasculitis lesions differ from urticaria lesions?
Urticarial vasculitis lesions are typically more painful than itchy and often display ecchymotic or hyperpigmented areas during resolution.
## Footnote
Unlike urticaria, they usually last longer than 24 hours.
73
What is acute urticaria?
The occurrence of spontaneous wheals or angioedema lasting less than 6 weeks
## Footnote
Precipitating factors are present in 50% of cases, commonly including infections, drug reactions, and food intolerance.
74
What is chronic urticaria?
The occurrence of daily, or nearly daily, wheals or angioedema lasting more than 6 weeks
## Footnote
Develops in 20-45% of patients presenting with acute urticaria.
75
What percentage of individuals with chronic urticaria are affected by chronic spontaneous urticaria (CSU)?
60–80% of individuals with chronic urticaria
## Footnote
CSU is characterized by more persistent wheals than chronic inducible urticaria.
76
What are common precipitating factors associated with chronic spontaneous urticaria (CSU)?
* Infections
* Drugs
* Food
* Psychological factors
## Footnote
CSU can be autoimmune or autoallergic.
77
What can exacerbate symptoms in chronic spontaneous urticaria (CSU)?
* Heat
* Stress
* Various medications (e.g., aspirin, NSAIDs)
* Pseudo allergens
## Footnote
Up to 30% of cases are associated with functional IgG antibodies to IgE receptors.
78
What is chronic inducible urticaria (CIU)?
Characterized by its ability to be triggered consistently and reproducibly in response to a specific stimulus
## Footnote
Wheals appear approximately 5 minutes after the stimulus.
79
Describe the morphology of wheals.
Wheals may be a few millimeters to several centimeters in diameter and can be round, form rings, a map-like pattern, or giant patches.
80
What is the typical duration of wheal lesions?
Each lesion may last a few minutes to several hours and resolves within 24 hours at each affected site.
81
What is angioedema?
Develops when small blood vessels leak watery liquid, causing swelling, often localized to areas like the face, hands, and feet.
82
What initial treatment is recommended for urticaria?
Non-sedating antihistamines with uptitration of dose (up to 4x daily)
## Footnote
Fexofenadine and cetirizine are excreted by the kidneys, while loratadine and desloratadine are metabolized by the liver.
83
When should sedating antihistamines be considered?
Only if there is no response to a full dose of non-sedating antihistamines
## Footnote
They should be added into Step 2 and taken periodically at night.
84
What are common medications that may aggravate symptoms of urticaria?
* Aspirin
* Other NSAIDs
* Codeine
## Footnote
These medications can worsen urticaria symptoms.
85
When should a patient with urticaria be referred to secondary care?
If not responding adequately to a dose of 4 non-sedating antihistamines per day.
86
What is urticarial vasculitis?
Lesions persist for more than 24 hours, may burn and itch, and can be painful or tender, potentially fading to leave a bruise.
87
What are autoinflammatory syndromes associated with urticaria?
* Schnitzler's syndrome
* Systemic juvenile idiopathic arthritis (Still's disease)
* Cryopyrin-associated periodic syndromes
## Footnote
These are rare conditions mediated by increased interleukin-1 secretion.
88
What systemic symptoms can accompany autoinflammatory syndromes?
* Recurrent fever
* Arthralgia or arthritis
* Fatigue
## Footnote
These syndromes often have a diagnostic delay of many years.
89
What is a common characteristic of lesions in urticaria?
A smooth, elevated, blanched wheal surrounded by an erythematous flare
90
How long does each lesion of urticaria generally last?
30 minutes to 4 hours
91
Define acute urticaria
Occurrence of spontaneous wheals or angioedema lasting less than 6 weeks
92
Define chronic urticaria
Occurrence of daily, or nearly daily, wheals or angioedema lasting more than 6 weeks
93
What are the two classifications of chronic urticaria?
* Spontaneous urticaria
* Inducible or physical urticaria
94
Name some types of inducible or physical urticaria
* Dermatographic urticaria
* Delayed pressure urticaria
* Cholinergic urticaria
* Cold urticaria
* Solar urticaria
* Aquagenic urticaria
95
What is the mainstay of treatment for urticaria?
Antihistamines
96
What is the initial dosing recommendation for a non-sedating antihistamine?
Once a day for 2-4 weeks
97
If the initial response to antihistamines is inadequate, what should be done?
Increase the dose to 1 tablet twice daily
98
What is the maximum recommended increase in antihistamine dosage if the response remains unsatisfactory?
Up to 4 times the usual dose
99
What should be considered when using higher doses of antihistamines?
Co-existent morbidities
100
Which antihistamines are excreted by the kidneys?
* Fexofenadine
* Cetirizine
101
Which antihistamines are metabolized by the liver?
* Loratadine
* Desloratadine
102
When should treatment for urticaria be restarted?
If urticaria recurs
103
What should be investigated in patients with urticaria?
Thyroid function tests and autoantibodies
104
When should patients not be investigated for allergy?
Unless there is a clear link between food and the onset of symptoms
105
When should cases of cold, solar, or contact urticaria be referred?
If they do not respond as expected or have unusual features
