New GP Derm Flashcards
What is the medical term for acne?
Acne vulgaris
What is acne caused by?
Chronic inflammation
+/- localised infection in pockets within the skin (pilosebaceous unit)
What is a pilosebaceous unit?
Tiny dimpes in the skin containing haor follicles + sebaceous glands
What do the sebaceous glands produce?
Natural skin oils + sebum (waxy substance)
How does acne develop?
Acne results from:
* Increased sebum production → trapping of keratin (dead skin cells) → blockage of the pilosebaceous unit
* → Swelling + inflammation in the pilosebaceous unit
What increases and decreases the production of sebum?
- Androgenic hormones = increase sebum production (hence why acne is exacerbated by puberty)
- Anti-androgenic hormonal contraception = decreases sebum production
What type of acne does bacteria play a major role in?
Propionibacterium acnes
(Bacteria colonises the skin → excessive bacteria growth = can exacerbate acne)
(Treatments = aim to reduce these bacteria)
Define macules
Flat marks on the skin
Define papules
Small lumps on the skin
Define pustules
Small lumps containing yellow pus
Define comedones
Skin coloured papules representing blocked pilosebaceous units
Define blackheads
Open comedones with black pigmentation in the centre
Define ice pick scars
Small indentations in the skin that remain after acne lesions heal
Define hypertrophic scars
Small lumps in the skin that remain after acne lesions heal
Define rolling scars
Irregular wave-like irregularities of the skin that remain after acne lesions heal
What are the aims of acne vulgaris treatment?
- Reduce symptoms
- Reduce risk of scarring
- Minimise the psychosocial impact
Name the options for the management for acne and what order is the stepwise fashion (based on severity + response to treatment)?
- No treatment (if mild)
- Topical benzoyl peroxide (↓ inflammation, unblock skin, toxic to P. acnes bacteria)
- Topical retinoids (chemicals related to vitamin A; ↓ sebum production)
- Topical antibiotics (clindamycin) + benzoyl peroxide (↓ antibiotic resistance)
- **Oral antibiotics (lymecycline) **
- Oral contraceptive pill (stabilse hormones + ↓ sebum production) (Dianette = most effective combined contraceptive pill)
- Oral retinoids (isotretinoin) (highly teratogenic)
What is an effective last-line option for severe acne?
Oral retinoids e.g. isotretinoin
* Prescribed by specialist after other methods fail
* Follow-up + reliable contraception
* ** = Highly teratogenic**
What is the most effective combined contraceptive pill for acne treatment?
Co-cyprindiol (Dianette)
= Most effective due to its anti-androgenic effects
= High thromboembolism risk → discontinued after acne is controlled (not prescribed long-term)
How are oral retinoids (isotretinoin) (e.g. Roaccutane) effective?
- Reduce sebum production
- Reduce inflammation
- Reduce bacterial growth
Name a side effect of oral isotretinoin?
- Dry skin and lips
- Photosensitivity of the skin to sunlight
- Depression, anxiety, aggression and suicidal ideation (patients should be screened for mental health issues prior to starting treatment)
- Rarely Stevens-Johnson syndrome and toxic epidermal necrolysis
What is psoriasis
A chronic autoimmune condition that causes recurrent symptoms of psoriatic skin lesions
Is psoriasis genetic?
Clear genetic component - but no clear genetic inheritance
Approx. 1/3 patients have a first degree relative with psoriasis
Symptoms start in childhood in a 1/3 of patients
In basic terms, how does psoriasis present?
Patches of psoriasis are dry, falky, scaly, faintly erythematous skin lesions in raised + rough plaques - commonly over extensor surfaces of the elbows + knees + scalp
Simple pathophysiology of psoriasis
Skin changes = caused by the rapid generation of new skin cells → resulting in an abnormal buildup thickening of skin in those areas
What are the types of psoriasis?
- Plaque psoriasis
- Guttate psoriasis
- Pustular psoriasis
- Erythrodermic psoriasis
How does plaque psoriasis present?
- Thickened erythematous plaques with silver scales
- Commonly seen on the extensor surfaces + scalp
- Plaques are 1-10cm diameter
(Most common form of psoriasis in adults)
How guttate psoriasis present? And how in?
Guttate psoriasis = 2nd most common form of psoriasis, commonly presents in children
- Many small raised papules across the trunk + limbs
- Papules = mildy erythematous + can be slightly scaly
- Over time, the papules → turn into plaques
- Guttate psoriasis = often triggered by a streptococcal infection, stress or medications
- Often resolves spontaneously within 3-4 months
What is guttate psoriasis often triggered by?
Streptococcal throat infection
What is pustular psoriasis?
- Rare severe form of psoriasis
- Pustules = form under areas of erythematous skin
- The pus in these areas = not infectious
- Can be systemically unwell
- Treated as medical emergency - require hospital admission
What is erytherodermic psoriasis?
- Rare severe form of psoriasis
- Extensive erythematous inflamed areas - covering most of the surface of the skin
- The skin = comes away in large pathches (exfoliation) → resulting in raw exposed areas
- Medical emergency - requires hopsital admission
What form of psoriasis is most common in children, that is often triggered by a throat infection?
Guttate psoriasis
How might psoriasis present differently in children from adults?
In children - psoriasis plaques may be smaller, softer and less prominent
What are the 3 specific signs suggestive of psoriasis?
- Auspitz sign → small points of bleeding when plaques are scraped off
- Koebner phenomenon → development of psoriatic lesions to areas of skin affectsed by trauma
- Residual pigmentation of the skin after lesions resolve
How can a diagnosis of psoriasis be made?
Clinical diagnosis - based on the appearance of the lesions
What is the management for psoriasis?
- **Topical steroids **
- Topical vitamin D analogues (calcipotriol)
- Topical dithranol
- Topical calcineurin inhibitors (tacrolimus) are usually only used in adults
- Phototherapy with narrow band ultraviolet B light is particularly useful in extensive guttate psoriasis
- Severe + difficult to treat:** Methotrexate, cyclosporine, retinoids, biologic medications**
What are the two commonly used products prescribed for psoriasis?
(They contain a potent steroid + vitamin D analogue)
- Dovobet
- Enstilar
What are some associations of psoriasis?
- Nail psoriasis (nail changes that occur in psoriasis) → nail pitting, thickening, discolouration, ridging, onycholysis (separation of the nail from bed)
- Psoriatic arthritis (10-20%) → usually occurs within 10 years of skin changes - middle age
- Psychosocial → mood, self-esteem, social acceptance → depression + anxiety
- Other co-morbidities that increase the risk of cardiovascular disease are associated with psoriasis, particularly obesity, hyperlipidaemia, hypertension and type 2 diabetes.
What is impetigo?
A superficial bacterial skin infection - usually caused by a staphylococcus skin infection
Occurs when bacteria enter via a break in the skin
What are the 2 common causative organisms of impetigo?
- Staphylococcus aureus (most common)
- Streptococcus pyogenes
What is the characteristic feature of impetigo caused by a staphylococcus skin infection?
A ‘golden crust’
What are two classifications of impetigo?
- Non-bullous
- Bullous
Is impetigo contagious?
Yes very!
(Keep kids off of school)
How does non-bullous present?
- Non-bullous impetigo = typically occurs around the nose or mouth
- Exudate from the lesions → dries to form a ‘golden crust’
- Do not usually cause systemic symptoms or make the person unwell
Management of non-bullous impetigo?
- First line: Topical fusidic acid or hydrogen peroxide topical (1%)
- Second line: Oral flucloxacillin (more widespread or severe impetigo)
What is bullous impetigo caused by?
Staphylococcus aureus bacteria
What is the pathophysiology of bullous impetigo?
- Staphylococcus aureus = produce epidermolytic toxins that break down proteins that hold skin cells together → causes 1-2cm fluid filled vesicles to form → grow → burst → form ‘golden crust’ → heal without scarring
- Lesions = can be painful + itchy
Who does bullous impetigo typically present in?
- Neonates + children (under 2) (most common)
- Older children
- Adults
Which type of impetigo is likely to cause patients to have systemic symptoms (feverish + generally unwell)?
Bullous impetigo
What is the condition called in which bullous impetigo becomes widespread?
Staphylococcus scalded skin syndrome
What are the Ix for impetigo?
- First line: Clinical diagnosis
- Gold standard: Bacterial skin culture
What is the management for bullous impetigo?
Oral or IV flucloxacillin
IV if very unwell or at risk of complications
Name two complications of impetigo
- Cellulitis if the infection gets deeper in the skin
- Sepsis
- Scarring
- Post streptococcal glomerulonephritis
- Staphylococcus scalded skin syndrome
- Scarlet fever
What is folliculitis?
Folliculitis = an inflammatory process involving any part of the hair follicle
Folliculitis = most commonly secondary to infection
Causative organisms of follicultitis
- Bacterial (most commonly staphylococcus aureua)
- Fungal
- Viral
- Parasitic
What subset of patients can folliculitis particulary develop in?
Folliculitis can occur in patients with acne undergoing long-term oral antibiotic therapy and may mimic an acne flare.
Risk factors for folliculitis
- Trauma (shaving + extraction)
- Topical corticosteroid preparations
- Diabetes mellitus
- Immunosuppression (can cause eosinophilic folliculitis)
- Hot-tub use (‘hot-tub folliculitis - caused by Pseudomonas aeruginosa)
- Chronic inflammatory skin disease
A 26-year-old woman presents to the GP complaining of an erythema on her left leg. She admits to shaving the area 2-3 days ago. On examination, there is a small cluster of erythematous papules. A short course of oral antibiotics completely resolves the issue. Possible diagnosis?
Folliculitis
Signs and symptoms of folliculitis
Signs:
* Localised to shaving area
* Blistering (if severe)
* Subdermal mass (abscess formation if can occur in severe disease)
* Raised eosinophils
Symptoms:
* Erythema
* Papules (small, clusters)
* Pustules (small, white-headed)
* Pruritus (localised to affected area)
Investigations for folliculitis
Uncomplicated, superficial folliculitis is often managed in General Practice without the need for further investigation.
However, severe, persistent or recurrent episodes may warrant further tests:
* Bacterial skin swab: gram-positive cocci in Staphylococcus aureus infection
* Viral skin swab: moulding and clustering of keratinocytes is suggestive of Herpes simplex infection
* Skin scraping for mycology: hyphal forms seen in dermatophyte infection
* Skin biopsy: neutrophilic infiltrate in bacterial and fungal disease, lymphocytic in viral
Management of folliculitis
Conservative:
* Using clean, sterile razors for shaving
* Wearing loose clothing
* Antibacterial soap use
* Avoiding hot-tub use
Medical:
* Mild (all organisms): self limiting, no treatment required or trial of topical antibiotics
* Moderate (bacterial): oral flucloxacillin (Staph aureus) or oral ciprofloxacin (Pseudomonas spp.)
* Moderate (viral): oral aciclovir
* Moderate (fungal): ketoconazole, fluconazole, itraconazole
Surgical:
* Incision + drainage
* IV antibiotics
Complications of folliculitis
- Abscess formation (in severe infection)
- Sepsis (in severe infection)
- Scarring
A 10-year-old child presents with multiple small, firm, rough bumps on his hands. The lesions are skin coloured and have been present for a couple of months and are slowly increasing in size. They are not painful but the child is concerned about their appearance. Possible diagnosis?
Cutaneous warts
What virus are cutaneous (common warts) caused by?
Human papillomavirus (HPV) type 2 and 4
(Genital warts HPV 6 and 11)
The virus invades the skin through small cuts or abrasions and causes rapid growth of cells on the outer layer of the skin, leading to the formation of a war
Signs and symptoms of cutaneous warts
Signs:
* Firm, rough papules or nodules
* Interrupted skin lines over the warts
* Black dots within the wart (thrombosed capillaries)
Symptoms:
* Often asymptomatic
* Ocassionaly tender (particularly verrucas)
Investigations for cutaneous warts
Warts = typically diagnosed based on their characteristic clinical appearance
Investigations to consider:
* Biopsy
Management of cuatneous warts (common warts)
First-line:
* Watchful waiting (especially children)
* Topical salicylic acid
Second-line:
* Cryotherapy (involves freezing the wart with liquid nitrogen and is typically used if topical salicylic acid is ineffective)
* Immunotherapy
A 34-year-old farmer attends his GP due to persistent erythema and pruritus on his hands following the use of certain weedkillers. A skin-patch test reveals the particular allergen and subsequent avoidance of the substance has improved his symptoms. Possible diagnosis?
Contact dermatitis
Info: Pathophysiology of contact dermatitis
Contact dermatitis is a skin reaction caused by an external agent [1]. Contact dermatitis can be either:
- Irritant contact dermatitis (ICD)
- Allergic contact dermatitis (ACD)
ICD is caused by direct toxicity by an agent, whereas ACD is a delayed hypersensitivity reaction
Risk factors for contact dermatitis
- Occupation with frequent exposure to water and caustic material: compromise of the epidermal barrier allows penetration by allergens, e.g. labourers, farmors, chefs
- History of atopic eczema
Signs and symptoms of contact dermatitis
Signs:
* Acute onset: ICD (minutes to hours for severe irritants) ACD (24-72 hours if previously sensitised)
* Affecting hands + face
* Sparing of non-exposed areas
* Persistence of symptoms: ICD can take 3-6 weeks to resolve, ACD usually resolves within a few days
* Scaling: chronic contact dermititis
* Lichenification: chronic contact dermatitis
Symptoms:
* Erythema
* Pruritis (more in ACD than ICD)
* Burning (more in ICD than ACD)
* Vesicles (more common in ACD than ICD)
Investigations for contact dermatitis
- Skin patch testing: to identify allergen
- Repeated open application test: to reproduce ACD at application site
Management of contact dermatitis
IRRITANT CONTACT DERMITITIS:
* First-line: Avoidance of irritant + skin emollients (simple moisturisers)
* Second-line: Topical corticosteroids (hydrocortisone, betamethasone)
ALLERGIC CONTACT DERMITITIS
* First-line: Avoidance of allergen + topical corticosteroids (hydrocortisone, betamethasone)
* Second-line: Topical calcineurin inhibitors: tacrolimus, pimecrolimus
* Third-line (or severe disease): oral corticosteroids (prednisolone, dexamethasone); phototherapy; immunosuppressants (azathioprine, ciclosporin)
Complications of contact dermatitis
- Secondary impetigo: bacterial infection due to compromised skin barrier
- Post-inflammatory hyperpigmentation
What is an ‘exanthem’?
An exanthem = an eruptive widespread rash
What are the 6 viral exanthemas?
First disease: Measles
Second disease: Scarlet Fever
Third disease: Rubella (AKA German Measles)
Fourth disease: Dukes’ Disease
Fifth disease: Parvovirus B19
Sixth disease: Roseola Infantum
“My Sister Really Doesn’t Pick Rashes.”
What are the clinical features of measles?
- Fever
- Coryzal
- Conjunctivitis
- Koplik spots (greyish white spots on the buccal mucosa) → appear 2 days after feber → pathognomic for measles
- RASH (erythematous macular rash with flat lesions): starts on face (classically behind the ears) (3-5 days after fever) → spreads to rest of body
Koplik spots = pathognomonic for measles, meaning if a patient has Koplik spots, you can diagnose measles.
Treatment of measles
- Measles = self resolving after 7 – 10 days of symptoms.
- Children should be isolated until 4 days after their symptoms resolve.
- Measles = a notifiable disease and all cases need to be reported to public health.
- 30% of patients with measles develop a complication.
Complications of measles
- Pneumonia
- Diarrhoea
- Dehydration
- Encephalitis
- Meningitis
- Hearing loss
- Vision loss
- Death
What is scarlet fever caused by?
Scarlet fever = caused by Group A streptococcus infection → usually tonsilitis (not caused by a virus)
Specifically an endotoxin produced by streptococcus pyogenes (group A strep) bacteria
Characteristic features of Scarlet fever
- Strawberry tongue
- Red-pink blotchy, macular rash with ‘sandpaper’ skin (trunk → spreads outwards)
- Red flushed cheeks (usually)
Clinical features of Scarlet fever
- Strawberry tongue
- Red-pink blotchy, macular rash with ‘sandpaper’ skin (trunk → spreads outwards)
- Red flushed cheeks (usually)
- Cervical lymphadenopathy
- Sore throat
- Fever
- Lethargy
Treatment of Scarlet fever
Phenoxymethylpenicillin (penicillin V) for 10 days
(To treat the underlying streptococcal bacterial infection)
Is Scarlet fever a notifiable disease?
Yes
Children should be kept off school until 24 hours after starting antibiotics.
Apart from Scarlet fever, what other conditions can group A streptococcus cause?
- Post-streptococcal glomerulonephritis
- Acute rheumatic fever
Clinical features of Rubella
- Milder erythematous macular rash (face → rest of body) (more mild than measles) - lasts 3 days
- Mild fever
- Joint pain
- Sore throat
- Lymphadenopathy (behind ears + back of neck)
Management of Rubella
- Supportive + self-limiting
- Notifiable disease to public health
- Children should stay off school for at least 5 days after the rash appears.
- Children should avoid pregnant women.
Complications of Rubella
Rare:
* Thrombocytopenia
* Encephalitis
Why is rubella so dangerous in pregnancy?
Rubella in pregnancy → can lead to congenital rubella syndrome
Rubella syndrome (triad):
* Deafness
* Blindness
* Congenital heart disease
What is Duke’s disease?
No specific organism has been found
It is very common for children to get non-specific “viral rashes”. It is likely that “fourth disease” was used to describe these non-specific viral rashes that are now understood to be caused by many potential viruses
BS really?
What virus causes slapped cheek syndrome (erythema infectiosum)?
Parvovirus B19 virus
Clinical features of slapped cheek syndrome (erythema infectiosum)
Starts:
* Mild fever
* Coryza
* Non-specific viral symptoms (muscle aches, lethargy)
After 2-5 days:
* Rash appears rapidly: bright red rash on both cheeks
Few days later:
* Reticular midly erythematous rash (trunk + limbs) - can be raised + itchy
Treatment for slapped cheek syndrome
- Supportive (plenty of fluids + simple analgesia)
It is infectious prior to the rash forming, but once the rash has formed they are no longer infectious and do not need to stay off school.
Which patients are at risk of developing complications when infected with parvovirus B19 (slapped cheek syndrome)?
- Immunocompromised patients
- Pregnant women
Patients with haemoatological conditions:
* Sickle cell anaemia
* Thalassaemia
* Hereditary spherocytosis
* Haemolytic anaemia
These patients need:
* Serology testing → to confirm diagnosis
* Full blood count + reticulocyte count → check for aplastic anaemia
People that would be at risk of complications that have come in contact with someone with parvovirus prior to the rash forming, should be informed and may need investigations.
What are some major complications parvovirus B19 infection?
- APLASTIC ANAEMIA
- Encephalitis or meningitis
- Pregnancy complications including fetal death
- Rarely hepatitis, myocarditis or nephritis
What viruses cause Roseola Infantum?
Human herpes virus 6 (HHV-6) and less frequently by human herpes virus 7 (HHV-7)
Clinical features of Roseola Infantum
Infection → 1-2 weeks → high fever (up to 40C) comes on suddenly - lasts for 3-5 days → disappears suddenly
- Coryzal symptoms
- Sore throat
- Swollen lymph nodes
- When the fever settles → rash appears for 1-2 days
- Rash = mild erythematous macular rash across arms + legs + trunk + face → not itchy
Main complication of Roseola Infantum
Febrile convulsions - due to the high temperature
Immunocompromised patients = may be at risk of rare complications:
* Myocarditis
* Thrombocytopnia
* Guillain-Barre syndrome
