Common Skin Infections Flashcards
What is cellulitis?
A common bacterial infection of the deep subcutaneous tissue.
Describe the symptoms of cellulitis?
Red skin
Painful
Hot to the touch
Swelling
Can develop blisters, erosions and ulcerations
Systemic symptoms due to infection- fever, malaise, tachycardia, fatigue, rigors
What is erysipelas?
Erysipelas is an infection of the superficial layers of the skin, cellulitis is an infection of the lower dermis and upper subcutaneous tissue. They;re often considered together due to similar features.
What conditions make an individual more prone to cellulitis?
Previous episodes of skin disease Cuts in the skin Insect bites IVDU Alcohol excess Swollen limbs due to- Nephrotic syndrome, RHF, lymphoedema, venous insufficiency, CKD Liver disease Obesity Poorly controlled diabetes (hyperglycaemia feeds infection and there is reduced tissue repair) Immunosuppression
What are the most common causes of cellulitis?
Streptococcus pyogenes (2/3 of cases) Staph aureus (1/3 of cases)
Describe the appearance of cellulitis?
Most commonly see in the lower limbs but any area of skin can be affected, not it is most often unilateral. If bilateral other causes should be considered.
Redness
Swelling
Increased temperature
Pain
Edge is shart in erysipelas and ill-defined in cellulitis
Area of redness spreads, ascends from the lower leg
How does the border of redness differ with cellulitis and erysipelas?
Erysipelas- the border is sharp and raised
Cellulitis- the border is less well defined
How are cellulitis and erysipelas diagnosed?
History and clinical examination
What are some complications of cellulitis?
Septicaemia- do blood cultures and monitor closely
Necrotising fasciitis- if infection spreads in the fascial planes- severe pain that is worse than expected, skin pallor, loss of sensation and necrosis.
Spreading infection
Endocarditis
Abscess formation
Where does commonly erysipelas affect?
Legs
Less commonly the face- infection of the face can increase the risk of meningitis.
How is cellulitis or erysipelas diagnosed?
History and Examination
Bloods- FBC, ESR, CRP, U&Es, Culture (risk of septicaemia)
CXR- Risk of pneumonia
Doppler ultrasound- if suspecting DVT or peripheral vascular disease
Note- If suspecting complication of necrotizing fasciitis and MRI should be done.
What is the management for cellulitis or erysipelas?
Swelling and redness should be marked to monitor spread
Oral antibiotics for uncomplicated case e.g. flucloxacillin, amoxicillin.
IV Antibiotics for severe cases and systemic upset. Include fluid and oxygen if required. Minor for sepsis. Follow local guidelines for ABx therapy.
Supportive Therapy- Raise leg, IV fluids (depends on cause), monitor temperature, analgesia…
What is impetiogo?
Impetigo is a skin infection that is most often caused by staph aureus but may less commonly be caused by strep
Which age group is impetigo most common in?
Young children and infant
But can affect adults if they are immunosuppressed
What skin conditions increase an individuals risk of developing impetigo?
Atopic dermatitis/eczema
Scabies
Due to breaks in the skin which reduce barrier immunity and so can result in secondary bacterial infection.
Describe the features of impetigo?
Initially small pustules
These tend to break away easily and this results in the formation of patches with yellow crusts
These are small at first but can increase in size.
How can impetigo be spread?
Through scratching of lesions it can be spread around the body, it is therefore advised to avoid touching the lesions and to wash hands afterwards if you do accidentally touch them.
What is the name given for impetigo that causes blisters to form?
This is bullous impetigo- there are small vesicles that evolve into flaccid transparent bullae.
What are associated symptoms of impetigo?
Lymphadenopathy
Mild fever
Malaise
What are some complications that can occur from impetigo?
Staphylococcal scalded skin syndrome
Cellulitis
Septicaemia
If Strep- Post Streptococcal glomerulonephritis, Rheumatic fever
How is impetigo diagnosed?
It is normally diagnosed clinically based on the appearance and features.
Swabs may be taken for MC+S
Bloods- FBC, Culture (if could be septic and systemically unwell)
What is the treatment for impetigo?
Clean the plaque/crusts with water to gently remove the crusts
Antibiotic creams such as fusidic acid/mupirocin, less commonly used due to emerging resistance. Antiseptic washes may be used e.g. chlorhexidine, povidone iodine
Oral antibiotics e.g. flucloxacillin/erythromycin if severe/systemically unwell (fever/malaise)
Avice careful hand hygiene, wash hands after applying creams, don’t touch lesions if possible, avoid sharing towels, flannels, clothes, wash these after use at high temperature with laundry bleach.
Wash and change clothing and bedding daily during first few days.
How long should children spend off school after impetigo?
At least 48 hours after starting oral Abx
Or when the crusts have dried up
What is scabies?
Scabies is an intensely itchy rash that is caused by a parasite mite that lives on the skin surface
How is scabies spread?
Through skin to skin contact- rarely through sharing towels, clothes, bedding
Where are people at risk of catching scabies?
Densely populated areas Poverty areas Institutionalised care e.g. in prisons and care homes Refugee camps Selly oak Immunosuppressed people
What are scabies burrows?
Scabies burrows are created after mating between the scabies parasites. They male dies and the female burrows into the skin to lay the eggs. They can be seen as raised grey or reddish lines on the surface of the skin extending red areas. They are found in the web-spaces between fingers, on the palms, wrists, elbows, nipple, armpits, buttocks, penis and heels.
What are the features of a scabies manifestation?
Very intense itching with is more severe at night and often disturbs sleep
Scabies rash- papules, vesicles, pustules, erythema and nodules affecting the finger webs, wrist flexures, axillae, abdomen, buttocks and groin
Excoriations and Eczematised
What is crusted scabies?
This is also called Norwegian scabies. It occurs when there are thousands of mites colonising a person. It is highly contagious.
It is seen in the elderly or immunosuppressed
How does crusted scabies present?
Generalised itchy scaly rash- often misdiagnosed as psoriasis or seborrheic dermatitis
Scaling if often more prominent in the finger webs, on wrists, elbows, breasts and scrotum
Itch may be absent or minimal
Can affect the scalp
How is scabies diagnosed?
History and examination features
Ask about other people in the house being affected
Dermatoscopy may show the mites
Microscopy may show the mites, eggs or feces
What is the treatment for scabies?
Scabicides- these are insecticides
5% Permethrin cream applied to all of the skin below the neck for 12 hours. Malathion liquid is an alternative. Two treatments are required one week apart as eggs can hatch.
Alternatively, for severe scabies or if institution oral Ivermectin may be used.
All clothes, bed sheets, towel should be washed at a high temperature.
What is folliculitis?
Inflammation of the hair follicles
What can cause folliculitis?
Infection-
Bacterial (most often staph), yeats, fungi, viral (HSV, Herpes Zoster)
Irritation due to ingrown hairs-
-After shaving, waxing. Any swabs taken will be sterile.
Occlusion-
-After use of emollients, moisturisers
Overuse of topical steroids
Inflammatory skin conditions
Acne vulgaris and rosacea are forms of folliculitis
Describe the features of folliculitis
Tender red spots often with surface pustules
Can affect the hair on any of the body surfaces
Folliculitis Barbae affects the beard area.
How is bacterial folliculitis treated?
Antiseptic creams
Antibiotics creams
If chronic- mild steroid creams may reduce inflammation and can be given in addition to the steroid creams.
Oral antibiotics
How might the cause of folliculitis be investigated?
Close inspections
Swabs taken from the site or any pus from the pustules may be used for MC and S, PCR…
What can cause folliculitis?
Infection
Occlusion
Irritation (e.g from shaving- pseudofolliculitis)
Various skin disease
Which yeast infection has been found to cause folliculitis? What is the treatment?
Malassezia
Treatment is topical or oral anti-fungals
E.g. clotrimazole, econazole, fluconazole
What is pseudofolliculitis?
This is due to ingrown hairs, which can be seen with a microscope. Can occur with shaving, waxing or plucking. Any swabs taken from the site will be sterile.
Where can re-infection commonly come from for folliculitis affecting the beard area? (Folliculitis barbae)
This can come from the nose and no nasal anti-biotic ointments may be given that can be applied to the inside of both nostrils
What is the name for fungal infections which affect the scalp?
Tinea capitis- usually result in scaling and hair loss but can sometimes cause folliculitis.
Which virus causes viral warts?
Human papilloma virus causes viral warts (this also causes verrucas)
There are over 100 types of HIV causing papillomas/warts/cancers
Which patients are prone to developing warts?
Immunosuppressed patients- this includes patients with HIV and those taking immunosuppression.
What process causes the development of a wart?
Keratinocyte proliferation- hyperkeratotic so have a hard surface
How is HPV spread?
Direct skin to skin contact (this is also how it spreads from one area of the body to another)
Sexually transmitted too.
What is a dangerous risk of HPV?
Some strains are oncogenic and increase the risk of cervical, anal, penile and vulval cancer.
