Hives

Question 1

What is urticaria also known as?

Answer 1

Hives/Welts

Question 2

Describe Hives

Answer 2

Can have flat or raised above the plain of skin

Hives/Welts move and are very itchy and will not involve pus

Question 3

Describe the difference between hives, psoriasis, eczema, and contact dermatitis

Answer 3

Psoriaisis tends to occur in one spot
Eczema appears reptively on same area
Contact Irritant - WIll be in contact with an irritant and rash will develop where the irritant has contacted

Hives will move and will not have the rawness that is associated with eczema

Movement of hives is classic along with itchiness

Question 4

Define utricaria

Answer 4

Pruritic plaques with pale, centrally edemateous wheals surrounded by erythematous flare regions
–> Lesions wax and wane over hours to days, are transient, and change size and shape and persist for less than 24 hours

Question 5

What can help with the differential diagnosis of hives?

Answer 5

Hives will go away unless have chronic utricaria
–> Move and are itchy

Question 6

Describe the main presentation of Hives?

Answer 6

Main –> Itchy raised welts that occur after exposure to an allergen and/or host of other non-allergen triggers
–> Allergic reaction is not the case all the time; can have non-allergenic causes as well

Red, warm, and mildly painful to touch
Can be small, round, and ring-shaped or large and randomly shaped

Question 7

How does Hives present on darker skin?

Answer 7

Harder to diagnose
Reddened, itchy welts that may be triggered by exposure to certain foods, medications or other susbtances

Question 8

Describe the etyiology of Hives

Answer 8

Allergic and Non-Allergic to:
1) Foods, drugs
2) URTI’s (especially in children)
3) pressure/Vibration
4) Cold Temprature
5) Stress/Nerves

• Basically anything can cause hives and may never know what the cause was
• Many individuals will be quick to label it as allergic if hives develop - Not the case
• Does not mean you are now allergic to something - often can still take the drug, does not mean you will have anphylaxis (need involvement of a second system)

Allergies to x,y,z –> Main symptom here is a skin reaction - Body thinks the substance is foreign and when seen later will launch a reaction that could maybe lead to anaphylaxis

Question 9

Describe the pathophysiology of hives

Answer 9

Occurs when a trigger causes high levels of histamine and other chemical messengers to be released by the skin

These substances cause the blood vessels in the affected areas of the skin to open up (often resulting in redness or pinkness) and become leaky

The extra fluid in the tissue causes swelling and itchiness

Question 10

What can cause the release of histamine leading to hives?

Answer 10

Histamine is released for many reasons including:

1) An allergic reaction - food allergy, insect bite
2) Cold or heat exposure
3) Infection such as a cold
4) certain medications such as NSAIDs or antibiotics

Often no onvious cause can be identified

Question 11

What is a common cause of hives in children? Issue here?

Answer 11

When a cause for hives can be found, it is most likely a viral infection

Viral URTI’s cause about 40% of hives reactions

Hives reaction resolve as the infection resolves

• Often a drug will get the blame here

Question 12

Describe Stress Rash

Answer 12

Stress rashes often take the form of hives

• Blotchy areas can be as small as a pencil tip or aas large as a dinner plate

Areas affected by hives will likely be itchy

Question 13

How long do hives from a viral infection last?

Answer 13

Hives caused by a viral infection are typically acute, and usually last from four to 24 hours

Question 14

Describe the clinical presentation of Hives

Answer 14

Lesions last 1-24 hours up to several days
–> Their locations can change over this time

Very itchy

Usually benign (but can be part of the naphylaxis/angioedema complex)

Question 15

Describe the prevalence of Hives

Answer 15

Approx. 20% of the population have had hives

If they stay consistent for a long time in ONE spot, may be something else

Chronic Form –> 1%
- Triggers will rarely be known
- Chronic Idiopathic Utricaria - Itchy long term

Question 16

Describe Hives and differential diagnosis? Most common cause? When are hives the worst?

Answer 16

If not itchy, Not hives

A very common cause of hives are URT infections (within the last 6 weeks); most common cause in children - Likjely to blame the drug although virus

Typically hives last no more than 24 hours in ONE spot (if longer than 24 hours, start to think of alternate diagnosis)

Hives are worse at night time (because natural cortisol levels are less at night)

Question 17

Describe an aggressive approach to the treatment of Hives

Answer 17

Dual Therapy (often an oral second gen antihistamine is enough)

1) Second Generation Anti-histamine - Cetirizine
–> H1 receptor antagonists
–> often enough for therapy

2) Zantac - H2 Antagonist
- ACid receptos in the GI system - Aggressive approach

Most evidence suggests that a second gneeration anti-histamine is enough to cover the vast majority of what we need

Question 18

Describe the relationship between hives and anaphylaxis with medication therapy

Answer 18

Hive lesions move around

Hives are generally called an allergic reaction, but most are not due to that. Most patients have had a cold or virus which more often is the cause 9especially with children)

Easy to blame antibiotics but only 1-3% of penicllin skin reactions are actually an allergy
- The utricaria will last about 1-2 weeks in these cases
- On the next exposure of the antibiotics, most will not progress to something worse (like anaphylaxis)

If the person is truly allergic, they have to be sent home with an Epi-pen
- Sometimes may be done with just a rash, but for sure with any evidence of wheezing, lip swelling

Question 19

What is the realistic expectation regarding anaphylaxis and hives?

Answer 19

Most hives will not lead to anaphylaxis

• Next exposure leading to anaphylaxis - Can ahppen; however, majority of hives are not going to be allergic in nature

Legal over clinical here - Often listed as an allergy on the patients profile as an allergy

Question 20

Describe the treatment of hives?

Answer 20

Avoid the trigger (easier said than done)

Second Gneration Anti-histamines
- Drugs of choice for itch
- Try regular dose for a few days
- If no help after 2 weeks, MD may try increasing the dose 2-4X

High speciicity for Hives - Reasonable comfort zone as well

Calamine and cold packs can be useful as well for itch management

Question 21

Describe the safety of increasing a second genration antihistamine for the treatment of Hives? When is this done? Why?

Answer 21

Hives should not last long; 1-3 days and cause if often gone by then

If no help after 2 weeks, MD may try to increase the dose 2-4x

Can go 4x the dose of anti-histamine with a lot of confidence regarding safety

Confidence that it is hives –> regular doses may sense; however, someone may make the recommendation to go higher

Question 22

What are some adjunct therapies for hives? Are they effective?

Answer 22

1) 1st Generation Anti-histamines
- Some MD’s add a 1st gen anti-histamine for sedation HS
- No more antihistamine punch or faster acting than a second generation anti-histamine

2) H2 Anatagonists - Leap of faith; Skip it as H1 has the effect in hives

3) Leukotriene Antagonist (Monetlukast/Singulair) PRN - Not recommended for hives
- Hives is a histamine mediated process; allergic rhinitis and asthma leukotrienes are released
- SIngulair not that effective as an agent fro leukotrienes

4) Steroid burts
- Hospital territory and angioedma present
- Massive anti-inflammatory punch
- Can be used for a real bad reaction of hives that is not anaphylaxis to help reduce the inflammatory proces staking place

Question 23

How can a second generation anti-histamine dose be increased? Example?

Answer 23

Claritin 40 mg
- Diagnosed by MD
- How we get to 40 mg is irrelevant

1) CAn take all 40 mg at once
2) Can take 10 mg to start, 10 mg later if still there, another 10 mg an hour later if better but still there, and another 10 mg an hour later if almost gone b8ut some itch
3) Can take 20 mg stat, if still around in 3 hours can take another 20 mg

• Depends on the situation but a high does at the start can be done

Question 24

Is topical therapy for hives reasonable?

Answer 24

Topical therapy can be difficult
- Itchy and movement presnet; so can be hard to predict where the hives will move

Question 25

Describe the role of topical agents in the treatment of hives

Answer 25

1) Benadryl Cream - NO

2) Clobetasone or HC
- Makes sense; however, can be difficult as moving so application of an agent is hard
- Large areas - Is the steroid having any benefit? Just natural movement of trhe hives
- Mixed opinions; often unnecessaray and not effective

3) Calamine - Absolutely
- TLC here, can be messy to apply

4) Menthol
- Need to use it at lower levels (> 1% counter irritant, <1% anti-pruritic)
- Evaporates off the skin, cooling and just a little bit of TLC

Question 26

When would steroids make sense in hives? Topical or oral?

Answer 26

Topical Steroids –> Not useful for mild hives
- Hives will move; playing catch up and may not help

Angioedema - Fluid shifting - COncern for anaphylaxis
–> ORAL STEROIDS HERE NOT TOPICAL

Systemic steroids - Should be reserved for pressur eurticaria, vasculitis utricaria and intractable chronic utricaria

Question 27

Define contact dermatitis

Answer 27

Localized rash/irritation caused by contact wth a foreign substance

Only the superficial regions of the skin are affected

CAN BE DUE TO AN IRRITANT OR ALLERGIC IN NATURE

Question 28

Describe the symptoms of contact dermatitis? Differentiation of hives?

Answer 28

Contact dermatitis results in large, burning and itchy rashes

Can take several days or weeks to heal

Utricaria in hwich a rash appears within minutes of exposure (internal or external) and then fades away within MINUTES TO HOURS

Contact dermatitis fades only if the skin is no longer in contact with the allergen or irritant

Question 29

Describe the difference between irritant and allergic contact dermatitis

Answer 29

Contact dermatitis requires contact
While either form of contact dermatitis can affect any part of the body, irritant contact dermatitis often affects the hands (b/c they come into contact with so much stuff)

Irritant - Usually confined to the area where the trigger actually touched the skin

Allergic - More widespread on the skin; still often localized to the region with contact

Question 30

SYmptoms of contact dermatitis. Differences between irritant and allergic?

Answer 30

Red Rash - Usual Rxn - This appears immediately in irritatnt, and allergic occurs 24-72 hours afte rthe exposure

Blsiters or wheals - where skin was exposed ti allergen or irritant

Itching, burning skin - Irritant more painful than itchy; allergic often itches

Question 31

How is hives differentiated from Contact dermatitis?

Answer 31

Hives - Can occur via contact or via ingestion of a substance, URTi, pressurem and otehr triggers

DO NOT SEE BLISTERING, nor does the skin burn

Itch is prominent and will move

Contact - More likely to be painful

Question 32

Describe irritant and allergic contact dermatitis and exposure of the substance

Answer 32

Contact Irritant - ALl about volume - AMount of chemical

Allergic - Less amounts, minuscule amounts of silver in an earring for example

Occurs in the same spot or around it