Infectious Rashes Flashcards
What are cold sores?
Contagious, recurrent blisters that spread by direct contact with mucosal surface or blister itself
Cold sores are primarily caused by herpes simplex virus (HSV).
What causes orofacial cold sores?
HSV 1
Orofacial cold sores typically appear on the mouth and face.
What causes genital cold sores?
HSV 2
Genital cold sores are less common than orofacial sores.
What are the initial symptoms of cold sores?
Tingling or burning sensation
This sensation is often followed by the formation of blisters.
What is the typical presentation of cold sores?
Blisters form in clusters on erythematous skin and crust over several days
The blisters are painful to touch.
How is cold sore infection confirmed?
Clinical diagnosis, Tzanck smear, or viral swab test
These methods help confirm HSV infection.
What is the typical management for oral herpes?
Usually self-limiting
Oral herpes typically resolves without intervention.
What is the treatment for genital herpes?
Topical 5% acyclovir ointment (200 mg 5x daily for 5 days)
Acyclovir is an antiviral medication effective against HSV.
What are the second-line drugs for genital herpes?
Famciclovir, valacyclovir
These can be used if acyclovir is not effective or tolerated.
What is the prophylactic treatment for herpes recurrence?
200 mg TDS for 6-12 months
This prophylactic treatment aims to prevent recurrence of herpes.
What is the prognosis for cold sores?
Cold sores are recurrent as HSV persists in sensory ganglia, but can be more chronic in immunocompromised patients.
Complications include erythema multiforme, eczema herpeticum, and affects CNS as it affects temporal lobe (memory loss).
What is eczema herpeticum?
Eczema herpeticum is a complication of herpes infections that can occur in individuals with eczema.
What is herpes zoster/shingles?
Herpes zoster/shingles is a painful rash on one side of the body in a dermatomal/band pattern, caused by reactivation of the latent varicella-zoster virus in the sensory ganglia (patient previously had chicken pox).
How is the rash from herpes zoster presented?
The rash is distributed in one or multiple adjacent dermatomes or in bands and doesn’t cross the midline.
The rash has clustered, crusting vesicles on an erythematous base.
What are systemic symptoms associated with shingles?
Systemic symptoms include fever and malaise.
What investigations are used for herpes zoster?
Investigations include scrape test or viral culture from blisters, Tzanck smear, and Direct fluorescent antibody (DFA) assays which are used to detect VZV.
What characterizes the rash in shingles?
Rash distributed in one/multiple adjacent dermatomes or in bands and doesn’t cross midline.
Rash has clustered, crusting vesicles on erythematous base.
What systemic symptoms may accompany shingles?
Systemic symptoms include fever and malaise.
What investigations are used to detect VZV?
Scrape test or viral culture from blisters, tzanck smear, Direct fluorescent antibody (DFA) assays.
These tests are used to detect VZV.
What is the management for shingles?
Acyclovir 800 mg 5x daily for 5 days in the week.
Most effective if taken within 24-72 hrs after onset. Can also prescribe analgesics.
What is the prognosis for shingles?
Should resolve in 2-3 weeks, but if untreated, it can lead to post-herpetic neuralgia and cranial nerve syndromes.
What are the characteristics of molluscum contagiosum?
Benign, self-limiting papules with a central dimple caused by molluscum contagiosum virus (MCV).
MCV spreads by skin-skin contact and is most common in children and sexually-active adults.
What is the presentation of molluscum contagiousum?
Skin-coloured and dome-shaped pearly papules with a central dot/dimple, containing a kerotic (cheesy) plug.
Is further investigation necessary for molluscum contagiousum?
No other investigations are necessary, but consider testing for HIV if the patient is otherwise completely healthy.
What is the management for the molluscum contagiousum if it does not resolve spontaneously?
Cryotherapy and curettage.
What is impetigo?
A common, contagious bacterial infection of the superficial layers of the epidermis.
What causes impetigo?
Caused by staphylococcus aureus and streptococcus pyogenes (Group A strep) transmission in the natural flora.
Who is most commonly affected by impetigo?
Most common in young children.
What are the two types of impetigo?
- Nonbullous impetigo
- Bullous impetigo.
What is the presentation of nonbullous impetigo?
Erythematous papules that rapidly evolve into vesicles and pustules that rupture, forming golden-yellow crusting.
Mostly on face.
What is bullous impetigo?
Bullous impetigo is characterized by flaccid bullae (large blisters) on non-erythematous skin that burst and ooze yellow fluid, which crusts over and leaves a scaly rim.
Usually found in skinfolds such as the trunk, axilla, groin, between buttocks, and between digits.
How is bullous impetigo diagnosed?
Bullous impetigo is diagnosed clinically.
What is the management for bullous impetigo?
Management includes topical antibiotics applied 3 times daily for 7-10 days, such as Mupirocin, retapamulin, and fusidic acid.
Systemic antibiotics are prescribed for all cases of bullous impetigo and for non-bullous impetigo with specific conditions.
What are the first-line and second-line systemic antibiotics for bullous impetigo?
First-line: Flucloxacillin; Second-line: Clarithromycin, erythromycin (for pregnancy).
What is folliculitis?
Folliculitis is an infection of hair follicles associated with staphylococcus aureus or exposure to pseudomonas aeruginosa in contaminated hot water.
It usually presents as asymptomatic but can be pruritic and painful, appearing as erythematous papules pierced by a central hair.
What is Furunculosis?
Deep infection of the hair follicle leading to abscess formation with accumulation of pus and necrotic tissue.
Tender, brightly erythematous, fluctuant, smooth nodules that rupture with purulent discharge; commonly found on the face, back of the neck, armpits, thighs, and buttocks.
What are the characteristics of Carbunculosis?
Rapid/simultaneous formation of many carbuncles (clusters of boils connected under the skin).
Erythematous, tender, inflamed nodules with multiple draining sinus tracts or pustules on the surface; presents on neck, back, thighs, and with systemic symptoms.
How is Furunculosis diagnosed?
Clinical diagnosis that can be confirmed with culture of pus drainage.
What is the management for Furunculosis?
Topical 1% clindamycin or 2% erythromycin; systemic antistaphylococcal antibiotics like vancomycin; incision and drainage for large boils.
What is Ecthyma?
Deep ulcerative skin infection that penetrates down to the dermis, caused by staphylococcus aureus and streptococcus pyogenes (Group A strep) transmission in the natural flora.