Derm: Shingles: Free MSRA Podcast

🎧 MSRA Deep Dive: Shingles – High-Yield Revision Essentials
Get exam-ready with this concise breakdown of shingles (herpes zoster) – covering pathophysiology, risk factors, red flags, and NICE-aligned management. Perfect for MSRA prep! 🧠

🧠 Core Learning Points

📌 Definition
• Reactivation of latent Varicella-Zoster Virus (VZV)
• Causes painful, unilateral, vesicular rash in a dermatomal pattern
• Commonly affects thoracic dermatomes or cranial nerves

📌 Pathophysiology
• After chickenpox, VZV lies dormant in sensory dorsal root ganglia
• Reactivation → virus travels along nerve → dermatomal rash
• Triggered by immunosuppression, age, stress
🧠 Mnemonic: “VIRUS” – VZV Reactivation In Unilateral Segment

📌 Risk Factors
• Age >50
• HIV (15x increased risk)
• Chemotherapy, immunosuppressants, long-term steroids
• Bone marrow transplant, lymphoma
• Stress
• Hx of chickenpox is a prerequisite

📌 Clinical Features
Prodrome (2–3 days):
– Burning/tingling pain
– Fever, malaise, local lymphadenopathy

Eruptive Phase:
– Red → vesicular → crusting rash in one dermatome
– Does not cross midline
– Lasts 2–4 weeks
– Ophthalmic zoster: affects eye – URGENT referral

Postherpetic Neuralgia (PHN):
– Pain lasting ≥30 days after rash resolves
– Risk ↑ with age

📌 Differentials
• HSV
• Contact dermatitis
• Eczema herpeticum
• Impetigo
• Insect bites
• Migraine/angina (if prodrome only)

📌 Infectivity & Transmission
• Shingles = not contagious as shingles
• VZV from blister fluid can cause chickenpox in non-immune individuals
• Avoid contact with:
– Pregnant women without immunity 🤰
– Neonates 👶
– Immunocompromised 💉

📌 Investigations
• Clinical diagnosis is usually sufficient
• Consider PCR of vesicle fluid if:
– Atypical features
– Immunocompromised patient
– Disseminated or severe disease
• IgM, Tzanck smear (older method) rarely used
• Eye involvement → urgent ophthalmology assessment

📌 Management (NICE/CKS aligned)

💊 Antivirals (start within 72h ideally):
• Aciclovir, valaciclovir, famciclovir
• Give to:
– Adults >50
– Immunocompromised
– Severe pain or non-truncal involvement
🕒 Start even after 72h if high-risk or ongoing vesicle formation

💥 Pain Relief
• 1st line: Paracetamol ± NSAIDs
• 2nd line: Amitriptyline, gabapentin, pregabalin, duloxetine
• Topical lidocaine patches may help
• Corticosteroids: reserved for severe acute pain (selected adults)

👁️ Referral Needed If:
• Ophthalmic zoster
• Immunocompromised
• Disseminated rash or complications
• Neurological signs (e.g., meningitis)
• Pregnant women
• PHN – consider pain clinic

📌 Complications
• PHN – burning nerve pain (up to 30% in older adults)
• Ophthalmic zoster – uveitis, keratitis, vision loss
• Ramsey Hunt syndrome – facial paralysis, ear pain, hearing loss
• Skin scarring, pigmentation
• Secondary infection
• Neurological – meningitis, encephalitis, myelitis
• Disseminated zoster

Episode Transcript

(00:00):
All right. Welcome back to the Deep Dive.
Today, we're getting into something really key for MSRA
revision shingles. Yep, shingles.
It causes that, well, often verypainful rash.
Exactly. And we're aiming for a high
yield overview here, really focusing on the core stuff you
need based on the revision material.
That's the plan. Conditions like this you really

(00:21):
need a clear, structured understanding for the exam.
We'll try and unpack the essentials quickly.
OK, let's dive in then. This condition shingles, what
actually is it like fundamentally?
OK, so shingles is a viral infection.
The the virus involved is the varicella zostrovirus.
VZV. VZV Wait, isn't that the chicken

(00:43):
pox? Virus.
That's it exactly. And that's probably the most
crucial starting point. Shingles isn't catching a new
virus, right? It's a reactivation that VZV
from when you had chicken pox maybe years ago.
It doesn't actually leave your body.
OK, so it just hangs around. Yeah, it goes dormant, sort of
hides out in your nerve cells. We're talking the sensory nerve
ganglia specifically. And then well later in life,

(01:04):
sometimes it wakes up again. That reactivation is shingles.
Got it. Reactivation of the old chicken
pox virus. So that leads us to ideology.
Why? Why does it wake up?
Yeah, good question. Like we said, it's the VZV
reactivating from that dormant state in the sensory nerves.
Whatever triggers it. Well, the honest answer is we

(01:25):
don't fully understand the exacttrigger in every case, but the
source material points to some pretty clear factors.
Generally it seems linked to a dip in your immunity to the
virus. OK, so if the immune system
isn't keeping it in check, whichbrings us to risk factors, who's
most likely to get this reactivation?
Number one factor is definitely age.

(01:45):
Getting older, especially being over 50, significantly increases
the risk. Makes sense.
And obviously you have to have had chicken pox in the past.
No chicken pox history, No shingles.
Right prerequisite. What else?
A weakened immune system is a really big one.
Like someone with HIV for example.
Exactly. The source actually highlights
HIV says shingles is about 15 times more common, but also
other things that suppress immunity.

(02:07):
Such as? Think about medications like
long term steroids or chemotherapy.
Certain conditions too like Hodgkin's lymphoma or people
who've had bone marrow transplants.
OK. And interestingly, high levels
of stress are also mentioned as a potential trigger.
That's a really useful list for revision and you know, it makes
sense clinically. The source mentions if you see

(02:29):
someone maybe younger, really severe shingles or it keeps
coming back, Yeah, you should maybe think, could there be an
underlying immunodeficiency thathasn't been diagnosed yet?
That's a really excellent clinical parole to take away,
definitely. OK, let's shift to the
pathophysiology. How does this reactivation in
the nerve actually 'cause that characteristic rash?
Right. So the VZV wakes up in those

(02:52):
sensory nerve ganglia. From there it basically travels.
It moves down the nerve fibre, following that nerves path right
out to the skin area that specific nerve supplies.
Like the nerve is a road and thevirus drives down it to one
specific patch of skin. That's a perfect analogy, yeah.
And because it sticks to that one nerve Rd, that single nerve
route. You get the dermatome pattern.

(03:13):
Exactly the rash appears in thatdermatome.
This whole reactivation thing isoften linked to a decrease in
cell mediated immunity. Which brings us back to why age
and immunosuppression are risks.You know the body's guard is
slightly down. Got it.
And common. Places the source mentions the
trunk is common, like dermatomesT1 down to L2.

(03:33):
OK, that really explains that band like rash usually just on
one side. Which makes me think of a sort
of exam style question. Imagine a patient comes in
painful blisters, rash, but it covers the whole left side of
their chest. Any wraps right around their
back, clearly crossing the spine.
Based purely on the pathophysiology, would you

(03:55):
immediately jump to shingles? And the answer thinking about
how it works has to be probably not right because shingles
follows 1 dermatome, it characteristically does not
cross the midline. That's the key take away.
Definitely. Maybe a memory tip.
Shingles sticks to its side. It never crosses the great
divide. Love it.
OK, so the rash pattern is oftena big clue, but are there other

(04:19):
things that could be? What about differential
diagnosis? Yeah.
Absolutely crucial. You've got to think broader if
you're looking just at the skin rash.
Could it be contact dermatitis? Maybe herpes simplex, which can
look similar. Sometimes impedigo insect bites,
even atopic eczema or eczema herpeticum.
OK, so other skin things. What about before the rash

(04:41):
appears that prodromal pain? That's the tricky bit.
That pain, depending on where itis, could mimic lays of things.
Chest pain, maybe abdominal pain?
If it's on the head, could it becluster headaches?
Migraine. And if it's near the eye or
forehead, you absolutely have toconsider Ramsey Hunt syndrome or
other eye issues. A good list to keep in mind.

(05:01):
Let's talk epidemiology, The UK picture.
How common is this? Well, the source says incidents
definitely goes up with age. Overall, about one in four
people in the UK will get it at some .1 in.
Four. Wow.
Yeah, and it's much more common in older adults.
Highest rates are apparently in the 70 to 79 age group.
But I mean, it can affect anyonewho's had chicken pox.
And that transmission thing, Canyou actually catch chicken from

(05:24):
someone with shingles? People get confused about that.
They really do. OK, let's clarify.
You cannot catch shingles from someone with shingles, right?
But the person with active shingles blisters can transmit
the VZV virus itself through direct contact with the fluid in
the blisters. Maybe droplets too.
If they transmit it to someone who has never had chicken pox,

(05:47):
that susceptible person won't get shingles, they'll get
chicken pox. OK, that's a super important
distinction for advising patients.
So shingles transmits VZV causing chicken pox in the non
immune. Got it.
And vaccination. Yep, there are shingles vaccines
available primarily aimed at older adults to boost their
immunity and reduce their risk. Makes sense.

(06:07):
The source also notes that chicken pox vaccine isn't
routine on the NHS schedule, partly due to some complex
population level theories about how it might affect shingles
rates in the short term. Interesting.
OK, let's move to clinical features.
What does it actually look like?Feel like stage by stage.
OK. So typically first you get the
prodromal period usually lasts say two or three days before you

(06:27):
see anything on the skin. And that's the pain.
That's usually the main thing, yeah.
Burning pain, often quite bad inthe area where the rash is going
to appear. Can even mess with sleep.
Anything else in that phase? Sometimes, maybe about 20% of
people feel generally unwell, bit of a fever, headache, tired.
They might notice itching or tingling paresthesia in that one

(06:47):
dermatome, maybe some tendernessor swollen glands nearby even
before the spots come out. OK, then comes the main event,
the eruptive phase. Right.
This starts as redness, maybe slightly raised erythematous or
macular, but it quickly turns vesicular.
Blisters. Yep, clusters of small blisters.
And again, the key thing visually follows.
The nerve path does not cross the midline.

(07:10):
If those blisters keep popping up for maybe five to seven days,
then they dry out, crust over and heal.
And it can be worse for some people.
Yeah, the source points out thatin older people, or if those
were immunocompromised, the rashmight be more widespread, take
longer to heal. That midline rule seems really
solid, then once it's crested over, is that it?
Not always, unfortunately. This is where the chronic phase

(07:31):
or posterpetic neuralgia PHN comes in.
The long term pain. Exactly.
Persistent nerve pain or pain that comes and goes in that same
area and at last for 30 days or more after the rash is healed or
crested can be really tough. Nasty.
Are there important variations like shingles in specific
places? Yes, definitely.
Ophthalmic shingles is a big one, affects maybe 1020% of

(07:53):
cases. That's when it affects the eye.
Precisely reactivation in the trigeminal nerve branch that
supplies the forehead, scalp, and crucially, the eye.
And why is that one so flagged? Because the risk to the eye is
serious, it's considered a medical emergency.
Needs a media, ophthalmology assessment, What can happen?
All sorts. Unfortunately.
The source lists things like severe pain, inflammation inside

(08:15):
the IUV, itis keratitis, eyelid drooping, ingrown lashes, optic
nerve issues, chronic inflammation, scarring, even
permanent vision loss. Wow, so symptoms.
Red eye vision changes, light sensitivity, tenderness around
the eye. OK, message received rash near
the eye. Immediate referral.
Got it. Any others?

(08:35):
Ramsey Hunt syndrome is mentioned too.
That's when herpes zoster affects the facial nerve near
the ear. Can cause facial paralysis, ear
pain, sometimes hearing loss or Vertigo.
Linked but a specific syndrome. OK.
So ophthalmic is a really urgentone to spot now investigations,
do we always need tests? Often no.

(08:56):
Diagnosis is usually clinical. That classic story, that typical
rash? Usually enough.
So when do you test? You test if it's not clear cut,
maybe the rash looks a bit weird, atypical, or if the
patient is immunocompromised because their presentation might
be unusual. And what tests are used?
Well, PCR molecular testing is very good.
Highly sensitive, reliable, pretty quick, usually done on
fluid from a blister. There's the older zinc smear

(09:18):
looking for giant cells and the blister fluid, but it's not as
good as PCR. You can look for specific IGN
antibodies in the blood during the acute phase and for eye
involvement, or if you suspectedspread they might use direct
fluorescent antibody tests or PCR on say corneal fluid or
blood. And going back to that
immunocompromised point. Yes, if the presentation is

(09:39):
really odd. Super severe, keeps coming back,
involves multiple dermatomes. The source emphasises.
You absolutely need to think about and investigate for an
underlying immune issue. Right.
Makes sense. OK, let's talk management.
How do we treat it? What are the goals?
Goals are pretty straightforward.
Reduce the pain, speed up the healing of the rash, and

(10:01):
crucially, prevent complications, especially that
posturepedic neuralgia. And the main tools.
Antivirals are key medicines like acyclovir, velocyclovir,
famscovir. When should they be?
Started ideally as early as possible.
The source really stresses starting within 72 hours of the
rash appearance. Is that for everyone?
It's. Particularly recommended for
certain groups, anyone immunocompromised, older adults,

(10:23):
say over 50 people with severe pain, or if the shingles effects
areas other than the trunk or limbs, especially the eye.
For younger, healthy people withmild trunk shingles, the benefit
after 72 hours is less clear, but it's often still considered,
especially if pain is significant.
Immunocompromised or older folksmight need longer courses or

(10:43):
higher doses too. OK, 72 hours is the magic
window, especially for higher risk groups.
What about pain relief and algesia?
Absolutely vital. Start simple paracetamol NS aids
if appropriate. And if that's not?
Enough. Then you escalate.
The source mentions neuropathic pain agents like amitriptoline,
gabapentin, pergabil and duloxetine.

(11:03):
These are often used for nerve pain.
Topical lidocaine patches can also be really helpful, both
acutely and for PHN. What about steroids?
Oral corticosteroids are sometimes considered mainly for
severe acute pain and immunocompetent adults, usually
within the first couple of weeks, but it's not routine.
Need careful thought. Got it.
And when do we need to get specialist involved referral.
OK, critical points here. Immediate referral or urgent

(11:27):
advice if there's any suspicion of eye involvement.
Ophthalmic Shingles. Right.
Immediate referral Also for anyone who is immunocompromised,
their disease can be much worse.Urgent referral if there are
signs of serious complications like meningitis or encephalitis.
Specialist advice for pregnant women is also recommended and

(11:48):
for that persistent nerve pain PHN, an early referral to a pain
clinic is often a good idea. Great summary and patient
advice. Yeah, remind them about
infectivity. Well, the blisters are active.
They can transmit VZV to people who haven't had chicken pox, so
avoid close contact with pregnant women who aren't
immune, newborns and immunosuppressed individuals

(12:08):
until all the lesions have fullycrusted over.
Keep the rash covered if possible.
OK, quick scenario then testing that management timing 65 year
old generally healthy shingles rash on their back calls you but
rash started four days ago. Do you start up like lower?
OK, 65 years old puts them in the slightly higher risk group
due to age. It's past the ideal 72 hour

(12:29):
window, but given the age and potential benefit in reducing
PHN duration severity, many guidelines would still support
considering antivirals. Although the benefit is less
certain than within 72 hours. It's a judgement call weighing
risks and benefits not as clear cut as within 72 hours for this
group. Good point, highlights a nuance.
So, treatment done, What's the typical prognosis?

(12:50):
For most people, pretty good. It usually resolves in say 2 to
4 weeks. The rash heels maybe leave some
slight skin colour changes but often no major scarring.
PHN. That's the big caveat, isn't it?
Bolisopetic neuralgia can lingerfor months, sometimes even
years. But starting those antivirals
probably does reduce the risk ofdeveloping it or its severity.
So prognosis depends a bit on age and health.

(13:12):
Definitely younger, healthier people tend to do very well.
Older patients, immunocompromised individuals,
pregnant women, they face a higher risk of complications.
Actual mortality is very rare, though, mainly seen in severely
immunocompromised patients with disseminated disease.
And prevention. We touched on vaccination.
Yeah, the shingles vaccine, likeShingrix, is recommended for
older adults to boost their immunity against VZV

(13:35):
reactivation. OK, less section then
complications. Let's just run through the main
ones again besides PHN. Right.
PHN is the most common affectingyou know, maybe 530%.
Much more likely if you're older.
Eye problems. Huge issue in ophthalmic
shingles. Pain, inflammation like uveitis,
keratitis, scarring, vision loss.

(13:55):
Really serious. Ramsey Hunt.
Yep. Facial paralysis, ear issues,
skin scarring, pigmentation changes are possible.
Secondary bacterial infection ofthe blisters can happen too.
Neurological rarer stuff. Yeah, things like Bell's palsy,
meningitis, encephalitis, myelitis, spinal cord
inflammation, even hemopresses or stroke in some cases.
And in the immunocompromised. The big worry there is

(14:19):
disseminated zoster. The virus spreading widely can
cause pneumonia, hepatitis, encephalitis, much more
dangerous. That's quite a list.
Really brings home why it's important.
Absolutely. It's definitely not just a rash.
So wrapping up thinking about this for a vision shingles, it's
more than just skin deep, isn't it?
It's a story about latent viruses, immunity, nerve

(14:39):
pathways and the potential for quite significant complications
from long term pain to site threatening emergencies.
Really highlights why spotting it, especially in those
vulnerable groups, and managing it properly is so crucial.
Well said. Understanding the pathway, the
risks, the red flags, that's a key.
And that was our deep dive into shingles.
Hopefully that's given you a clear high yield framework for

(15:01):
your MSRA revision drawing on those key source materials.
For more free MSRA revision resources, remember to check out
free m-sra.com and the full premium Revision toolkit is over
at pastthemsra.com. Yeah, best of luck with all your
studies.