Viral skin infection Flashcards
What are some examples of viruses that can affect the skin?
- Herpes simplex virus
- Human papillomavirus
- Molluscum contagiosum (Poxvirus)
- Varicella-Zoster virus
- Viral exanthems
What are some skin infections caused by Herpes Simplex Virus?
Oral warts (Cold sore)
Genital warts
Digital (Whitlow) warts
How can HSV infection affect the nerves?
The HSV virus enters the epidermis and penetrates the endings of sensory and autonomic nerves, causing cell death, acantholysis and sensory nerve damage
This results in a localised vesicular rash and neuropathic pain
What are some management options in HSV?
Acyclovir (Valacyclovir - Pro-drug)
Penciclovir (Famciclovir - Pro-drug)
How do acyclovir and penciclovir act as anti-virals?
They both are converted into monophosphates, then triphosphates, which prevent DNA polymerisation and this prevent DNA synthesis
What are some skin infections cased by HPV?
Peripheral warts
Genital warts (Condyloma acuminata)
Verrucas
What are some cancers that HPV infection increases the risk of?
- Vulvar cancer
- Oropharyngeal cancer
- Penile cancer
- Cervical cancer
- Anal cancer
How can COVID-19 affect the skin?
- Morbilliform rash
- “Covid toe” ( like a chilblain/ pernio like)
- Livedo reticularis ( lace like)
- Retiform purpura
- Urticaria
- Vesicular blisters ( like chicken pox)
- Telogen effluvium on recovery
How can multi-system inflammatory disease in children as a result of COVID-19 affect the skin?
- Mucositis
- Swelling and redness of hands and feet
- Conjunctivitis
- Polymorphic erythematous rash
What are the 4 main patterns of viral exanthem?
- Erythematous exanthems starting on the face
- Erythematous exanthems starting on the trunk
- Papulo-vesicular exanthems
- Exanthems of the extremitis
What are some erythematous exanthems starting on the face?
- Measles
- Rubella
- Erythema infectiosum
What are some erythematous exanthems starting on the trunk?
- Roseola
- Scarlet fever
- Unilateral laterothoracic exanthem
What are some papulo-vesicular exanthems?
Varicella-Zoster (Chicken pox and shingles)
Gianotti-Crosti syndrome
What is an exanthems of the extremities?
Hand, foot and mouth disease
What virus causes measles?
Paramyxovirus
What is the incubation period of measles?
1-3 weeks
What are some classical symptoms of measles?
- Fever ≥ 39ºC
- Generalised maculopapular rash
- Conjunctivitis
- Cough
- Coryza
- Koplik spots (Prodrome)
What are some complications of measles?
- Otitis media
- Laryngotracheobronchitis
- Febrile seizures
- Hecht’s giant cell pneumonia
- Appendicitis
- Myocarditis
What is the mainstay in measles prevention?
Measles vaccination
What are some side effects of measles vaccination?
Joint pain, fever, rash
Why may patients not get the measles vaccine?
Patients may not get the MMR vaccine due to vaccine hesitancy (Related to Andrew Wakefield)
What virus causes rubella?
Togavirus
How will rubella present?
This will follow the same rash distribution as measles, however will be less red and lasts a shorter period of time
What virus causes erythema infectiosum?
Human Herpes virus 6 (HHV-6)
How will erythema infectiosum present?
This presents with a slapped cheek appearance, with a reticular (Lacy) pattern
What is the name given to an initial infection of Varicella-Zoster?
Chicken pox
What is the name given to a re-activation of Varicella-Zoster in the body?
Shingles
Until what point is Varicella-Zoster infection contagious?
Until all lesions are crusted over
Where does Varicella-Zoster remain in the body?
It becomes latent in nerve roots
How does shingles occur?
The initial infection can become latent in nerve roots and in cases of immunosuppression or pregnancy, it becomes reactivated and spreads along a the nerve as shingles
How will shingles present?
papilo-vesicular rash along one dermatome
What are some possible complications of chicken pox?
- Bacterial sepsis
- Pneumonia
- Encephalitis
- Haemorrhagic complications
What are some possible complications of shingles?
- Meningoencephalitis
- Myelitis
- Cranial nerve palsy
- Vasculopathy
- GI ulceration
- Pancreatitis
- Hepatitis
In around 15% of elderly patients, postherpetic neuralgia can occur
What is Herpes-Zoster oticus (Ramsay-Hunt syndrome)?
This is a condition in which a shingles outbreak affects the nerves of the face, causing facial paralysis, hearing loss and a facial rash
