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Skin Infections 13th April 2011 Dr Samantha Triggs GPVTS ST2 Bacterial skin infections Viral skin infections Fungal skin infections Bacterial skin infections Why does skin get infected? There are multiple types of bacteria which are normally present on the skin. For example: Staphylococcus epidermidis and yeasts The presence of bacteria does not automatically lead to a skin infection What is the difference between colonisation and infections??? Colonisation: Bacteria are present, but causing no harm Infection: Bacteria are present and causing harm. A break in the epidermal integrity can allow organisms to enter and become pathogenic. This can occur as a result of trauma, ulceration, fungal infection, skin disease such as eczema Case History 1 A mother brings 5 yr old Johnny to surgery. He has developed this rash, which is weeping and crusting. What is the diagnosis? Impetigo A highly infectious skin disease, which commonly occurs in children. What is the likely causative organism? The causative organism is usually Staphylococcus Aureus (>90% cases1), but less often can be strep pyogenes. Begins as a vesicle, which may enlarge into a bulla. Weeping, exudative area with characteristic honey coloured or golden, gummy crusts, which leave denuded red areas when removed. May present as macules, vesicles, bullae or pustules Bullae are more prominent in staphylococcal infection and in infants What is the treatment? Impetigo Treatment: Mild localised cases - use topical antibiotic Polyfax Widespread or more severe infections – use systemic antibiotics, such as flucloxacillin (or erythromycin if penicillin allergic) Johnny’s mum asks if Johnny has to have any time of off school. What should you tell her? A: He does not have to be excluded from school so long as he is on antibiotics B: He has to remain off of school for 5 days from the onset of the lesions C: He must remain off of school until the lesions have crusted or healed D: He must remain off of school until he has completed the antibiotic course. Case History 2 A 27 year old business man attends surgery complaining of pain and itching in the beard area. You examine him and see the following: What is the Diagnosis? Folliculitis Inflammation of the hair follicle. Presents as itchy or tender papules and pustules at the follicular openings. Complications include abscess formation and cavernous sinus thrombosis if upper lip, nose or eye affected. What is the causative organism? Most common cause is Staph Aureus. Other organisms to consider include: Gram negative bacteria – usually in patients with acne who are on broad spec antibiotics Pseudomonas (“Hot tub folliculitis”) Yeasts (candida and pityrosporum) What is the treatment? Folliculitis treatment Topical antiseptics such as Chlorhexidine Topical antibiotics, such as Fusidic acid or Mupirocin More resistant cases may need oral antibioics such as Flucloxacillin Hot tub folliculitis – ciprofloxacin2 Gram negative – trimethoprim Cellulitis Infection of the deep subcutaneous layer of the skin Presents as a hot, tender area of confluent erythema of the skin Can cause systemic infection with fever, headache and vomiting. Erysipelas is more superficial and has a more well demarcated border Erysipelas What is the most common causative organsism? Cellulitis Streptococcus – Group A Strep Pyogenes. Others include Group B, C, D strep, Staphylococcus Aureus, haemophilus influenzae (children) and anaerobic bacteria (e.g Pasteurella spp. After animal bites) Treatment of cellulitis Oral Flucloxacillin or erythromycin if allergic Co-amoxiclav in facial cellulitis If severe systemic upset, may require admission for IV antibiotics. After the acute attack has settled, especially in recurrent episodes – consider the underlying cause Orbital cellulitis – refer urgently Case History 3 A mother phones the surgery about her 1 year old daughter Emma. Emma has been off her food and has had a slight runny nose. She has developed an erythematous rash. You arrange for her to attend the surgery for an appointment When Emma is seen in the surgery, the rash has started to spread, now there is superficial blistering and parts of the epidermis can be seen to shear off after gentle pressure Diagnosis??? Staphylococcal Scalded Skin Syndrome A superficial blistering condition caused by exfoliative toxins of certain strains of Staph Aureus Usually in children less than 5 yrs old Characterised by blistering and desquamation of the skin and Nikolsky's sign (shearing of the epidermis with gentle pressure), even in areas that are not obviously affected begins with a prodrome of pyrexia and malaise, often with signs and symptoms of an upper respiratory tract infection discrete erythematous areas then develop and rapidly enlarge and coalesce, leading to generalised erythema - often worse in the flexures with sparing of the mucous membranes large, fragile bullae form in the erythematous areas and then rupture Complications include hypothermia, dehydration and secondary infection. Treatment: ABC, refer urgently for IV antibiotics and fluids, may need referral to tertiary burns centre What is the diagnosis? Painful red nodule Furunculosis (boils) and carbuncles Deeper Staphylococcal abscess of the hair follicle Coalescence of boils leads to the formation of a carbuncle Treatment is with systemic antibiotics and may need incision and drainage. Consider looking for underlying causes, such as diabetes Case history 4 Mrs. Brown is a 78 yrs old type 2 diabetic. Mr Brown phones the surgery to request a home visit for his wife. He tells you that Mrs Brown has been feeling unwell for a few days with a pyrexia and headache. She has a red area of skin on her lower leg which is intensely painful. You arrange a home visit. When you arrive, Mrs Brown is quite lethargic and confused. Temp 39 degrees HR 115 bpm BP 90/50 You notice that the edge of the area starts to become purple. What is the diagnosis? Necrotising Fasciitis Rare, but serious and fatal condition Deep-seated infection of subcut fat and fascia which spreads along fascial planes. Vascular thrombosis leads to rapidly progressing infarction and death of skin and tissue, with systemic infection If suspected – refer urgently Case history 5 Mr Jones is a 22 year old who works as a personal trainer. He attends surgery as he wants to discuss his smelly feet! He tells you he has developed lots of “holes” in the soles of his feet. What is the diagnosis? Pitted Keratolysis Caused by Cornebacteria, which colonise the surface stratum corneum and produce areas of sharply demarcated maceration. Later develops a characteristic pitted appearance. Smells like rotten fish More common in young males, who wear tight occlusive shoes Treatment is aimed at reducing sweating and reducing bacterial colonisation: Breathable footwear Topical antibiotics (fusidin or mupirocin) Potassium permanganate, 20% aluminium chloride hexahydrate or 4% formaldehyde soaks can be affective Case History 6 Mr Smith is 40 yrs old who has a rash in his axilla. You are fortunate enough to have a wood’s light available in the room in your training practice! When you use the Wood’s light, the skin lesion shows a dramatic coral pink fluorescence. Erythrasma Colonisation of axillae or groin with Cornebacterium Minutissimum. Presents as a fine, reddish brown rash in the flexures, which is confluent and sharply marginated. Often misdiagnosed as a fungal infection Woods light illumination produces a characteristic coral-pink fluorescence. Treatment is with topical fusidin cream Viral Skin Infections Viral warts and verrucas Caused by human papilloma virus Very common Disappear spontaneously eventually If treatment is needed, options include: Salicylic acid topically – needs daily treatment and can take months Duct tape occlusion Cryotherapy Case history 7 A father brings his 3year old Daughter “Sarah” to surgery. She has developed an itchy rash: Diagnosis? Molluscum Contagiosum Which one of the following statements regarding this condition is incorrect? A: Usually spontaneously resolves B: Caused by an RNA pox virus C: Transmission is by direct contact D: There is no need for school exclusion E: Lesions usually heal without scarring Molluscum contagiosum Caused by DNA pox virus Common in children, but can occur at any age Spread by direct contact Presents as multiple small, pearly, dome-shaped papules with central umbilication Can occur at any site Usually resolve spontaneously in 6-18 months Resolution is heralded by the development of erythema around the lesions. Treatment is not usually necessary – simple reassurance and advice about reducing transmission. If treatment is necessary, options include: Piercing the lesion with an orange stick tipped with iodine Curretage imiquimod cream Herpes Zoster (Shingles ) Caused by reactivation of the chickenpox virus which has lain dormant in the dorsal root or cranial nerve ganglia Rash is preceded by a prodromal phase of up to 5 days of tingling or pain Then develop painful vesicles in a dermatomal distribution. Most common in thoracic and trigeminal areas Lesions become purulent, then crusted Healing takes place in 3-4 weeks Regarding infectivity and shingles: true or false? 1. Children with shingles should remain off school from 5 days from the onset of rash 2. Shingles in a pregnant mother does not carry a risk of her own fetus developing fetal varicella syndrome. 3. You can catch shingles from another person who has shingles 4. If not immune, you can catch Chicken Pox after contact with shingles Shingles treatment Aciclovir 800mg 5 times daily, for 7 days Rest, analgesia Complications include: Post herpetic neuralgia Secondary infection Guillain Barre Syndrome Occular disease Post-herpetic Neuralgia = pain lasting longer than 3 months after the rash. Which of the following is NOT a risk factor for developing post-herpetic neuralgia? A: Younger age B: More severe pain C: Severe rash D: Prodromal pain in dermatome Herpes Simplex Virus True or false: 1. HSV 1 is commonly sexually transmitted 2. The correct dose of aciclovir for HSV is 200mg 5 times daily for 5 days 3. Caesarean section should be recommended to all women presenting with primary episode genital herpes lesions at the time of delivery 4. Caesarean section is routinely recommended for women with recurrent genital herpes lesions at the onset of labour. Herpes Simplex Virus A highly contagious infection spread by direct contact HSV 1 = common coldsore HSV 2 usually presents on the genitalia Primary infection presents as acute, painful gingivo-stomatitis with multiple small intra-oral ulcers. Associated with fever, malaise and lymphadenopathy. Attacks are usually self-limiting Topical aciclovir can be used for oral lesions: 5 times daily for 5 days. Reduces duration of attack and duration of viral shedding. Types: Genital herpes Herpetic Whitlow Herpes Simplex Keratitis Eczema Herpeticum Fungal Infections Diagnosis? Dermatophyte infections 3 main genera: Trichophyton Microsporum Epidermophyton Invade the keratin of the stratum corneum Can be: Anthopophilic – contracted from humans Zoophilic – contracted from animals Geographic – contracted from soil Clinical appearance depends on the organism involved, the site and the host reaction Name the fungus!!! Tinea Corporis - Presents as scaly erythematous plaques with central clearing Tinea Cruris – commoner in males, assymmetrical erythema spreading from groin to upper thigh. Scaly advancing edge. Tinea Pedis: 2 main presentations: - Moist scaling between the toes, esp 4/5 webspace. - Mocassin type – fine, dry diffuse scaling over the whole sole. Tinea Manuum – diffuse dry scaling over the palm Tinea Capitis – commonest in children. Presents as non-itchy patches of hair loss with broken hairs. Tinea Unguium – Different presentation including: - White Onchomycosis - Oncholysis - Sub-ungural hyperkeratosis - Thickening of nail plate Case History 8 A 22 year old lady returns from a holiday in Spain. She has a tan. She has noticed hypopigmented lesions on her chest and back. Choose the diagnosis from the list below 1. 2. 3. 4. 5. Tinea Corporis Lyme’s Disease Psoriasis Pityriasis Versicolor Vitiligo Pityriasis Versicolor Common in young adults Occurs when the commensal follicular yeast Pityrosporum Orbiculare transforms into a mycelial form. Presents as fine, reddish-brown, scaly eruptions which are asymptomatic. Once the rash has gone, it leaves hypopigmented macules which fail to tan Treat with topical imidazole cream if fine scaling present Candida A commensal organism which becomes pathogenic under certain circumstances: With broad spec antibiotic use Pregnancy Immuno-compromise and diabetes Moist skin folds and areas of damp skin Can present at various sites, including orally, in genitals, groin, under breasts Management: drying affected area,removing causative factors. topical antifungal creams Any Questions???? References 1. 2. 3. 4. Kumar and Clark: clinical medicine 5th Edition. General Practice Notebook www.GPnotebook.co.uk RCOG Greentop guideline number 30: Genital Herpes in pregnancy Practical General Practice