Flashcards in Skin infections and infestations Deck (70)
How do HSV-1 and HSV-2 infections differ in manifestation?
HSV-1 is traditionally associated with orofacial infection, while HSV-2 is traditionally associated with genital infection, although there is considerable overlap in disease manifestations.
In what % of cases is primary infection of HSV asymptomatic?
80% of cases
Describe latency in HSV infections of both orofacial infections and genital infections
Latency is the establishment and maintenance of latent infection in nerve cell ganglia proximal to the site of infection:
o In orofacial infection the trigeminal ganglia are most commonly involved
o In genital infection the sacral nerve root ganglia (S2-S5) are involved
How do primary and secondary HSV infections differ?
Primary HSV infections are accompanied by systemic signs, longer duration of symptoms, and higher rate of complications. Recurrent episodes are milder and shorter
What is the most common presentation of HSV-1 infections?
When do most cases of herpetic gingivostomatitis occur?
Most cases arise between the ages of six months to five years
What are the clinical features of herpetic gingivostomatitis?
Clinical features include:
- systemic upset
- painful, white vesicles on tongue, buccal mucosa, palate, pharynx and lips
How long do the symptoms of herpetic gingivostomatitis persist?
The main symptoms persist for 5-7 days, and are fully resolved within two weeks
What is the proper name for cold sores?
What does recurrent infections of orofacial herpes simplex infections usually present as?
Herpes labialis (syn. cold sore)
What triggers Herpes labialis (syn. cold sore)?
Triggers are many, including UV-radiation, minor trauma and stress
Describe the clinical presentation of Herpes labialis
The clinical presentation of a cold sore is that of grouped vesicles, especially of the lips and perioral skin. The eruption is often preceded by a tingling, itching or burning sensation. Over a few days the vesicles form a crust, and the eruption resolves within 7-10 days
What can cause herpes genitalis?
Can be caused by both HSV-1 and HSV-2, and is usually sexually transmitted
Which HSV virus is more commonly associated with recurrent herpes genitalis?
How can herpes genitalis present in both men and women?
Systemic symptoms may precede the development of painful ulcers in both men and women
In women, ulcers can affect the external genitalia, as well as the vagina and cervix, which is involved in 70%-90% of cases. Dysuria may be severe and can cause urinary retention
In men, ulcers are most commonly seen on the glans, prepuce and shaft of the penis. Occasionally they can extend on to the scrotum, thighs, and buttocks. Approximately one-third of men will develop a urethritis
The perianal area and rectum may be involved with anal intercourse
What % of cases in women with herpes genitalis have their vaginas and cervixes affected?
70-90% of cases
Describe Inoculation herpes simplex
HSV can enter through an abrasion (e.g. shaving), to affect any part of the skin e.g. face, vulva etc
Lesions arise as vesicles, and sometimes bullae, either grouped as a plaque or scattered. Systemic upset tends to be minimal
Some well-described sites include the fingertips (a herpetic whitlow), where episodes can be recurrent, and on the face of rugby players, which is referred to as 'scrumpox'
What are some more unusual presentations of HSV infections?
• Eczema herpeticum
• Neonatal herpes simplex
• Disseminated herpes simplex
• Erythema multiforme
As with herpes zoster, a primary herpes simplex infection can lead to severe inflammation with the potential for damage to the cornea and conjunctivitis and blindness in the affected eye
Describe Eczema herpeticum
Atopic patients are at risk of developing extensive eruptions of herpes simplex known as eczema herpeticum
The condition presents with clusters of itchy or painful vesicles / punched-out monomorphic erosions, which may coalesce
Any site can be affected, most commonly the face and neck. Lesions can occur in normal skin or in sites actively or previously affected by atopic eczema or other skin conditions
New patches form and spread over a period of 7 to 10 days, and can become widespread
Describe neonatal herpes simplex
Genital herpes simplex at the time of delivery makes the risk of neonatal infection very high
Infection can also arise in the neonatal period
Symptoms vary from a localised cutaneous infection to disseminated herpes simplex
Describe disseminated herpes simplex
Those at risk are immunocompromised patients (e.g. those on chemotherapy), and neonates not protected by maternally acquired antibodies. It rarely occurs in healthy individuals
Cutaneous lesions may be clinically indistinguishable from those of herpes zoster
Systemic infection, such as hepatitis and encephalitis may develop with or without widespread cutaneous lesions.
Why is it important to distinguish early on between disseminated herpes simplex and disseminated herpes zoster?
The mortality from disseminated HSV is higher than that from disseminated zoster, so early recognition and treatment is essential
Describe Erythema multiforme (EM)
• Is characterised by macular, papular or urticated lesions, as well as the classical 'target lesions' distributed preferentially on the distal extremities. Mucosal surfaces may be involved
• EM is a hypersensitivity reaction usually triggered by infections, most commonly herpes simplex. The infection may present as a cold sore, or may be subclinical
How is primary herpetic gingivostomatitis and herpes genitalis treated?
Consider treatment with oral aciclovir 200 mg five times daily for 5 days. Adjust the dose accordingly in children
Alternatively use valaciclovir or famciclovir
Treatment will shorten the duration of an attack but does not prevent future attacks
In addition, for herpes genitalis, patients and their partners need screening for other sexually transmitted disease
How is recurrent herpes labialis treated?
Reduce risk factors eg advise on appropriate UV-protection
5% aciclovir cream can be helpful if used as soon as patients are aware that a recurrence is occuring
For very frequent / distressing attacks consider prophylactic aciclovir 200-400 mg BD (alternatively use valaciclovir or famciclovir)
How is recurrent herpes genitalis treated?
Treat with prophylactic aciclovir 400 mg BD (alternatively use valaciclovir or famciclovir)
How is recurrent herpes simplex associated with recurrent erythema multiforme treated?
Treat with prophylactic aciclovir 400 mg BD (alternatively use valaciclovir or famciclovir), adjust the dose accordingly in children
What is important to educate a HSV patient on for long term control and treatment?
It is important to recognise potentially life-threatening systemic infections, which are much more likely in immunocompromised patients and neonates
Patients need admitting urgently for treatment with high-dose intravenous antiviral therapy