Eczema, acne, psoriasis and common skin infections

Question 1

What is the definition of acne vulgaris?

Answer 1

Acne vulgaris is a chronic inflammatory skin condition affecting mainly the face, back and chest - it is characterised by blockage and inflammation of the pilosebaceous unit (the hair follicle, hair shaft and sebaceous gland). It presents with lesions which can be non-inflammatory (comedones), inflammatory (papules, pustules and nodules) or a mixture of both.

Question 2

What are the 5 stages of the development of acne?

Answer 2

1) Basal keratinocyte proliferation in pilosebaceous follicles 2) Increases sebum production 3) Bacterial colonisation with Propionibacterium acnes 4) Inflammation 5) Comedones (black and white heads) blocking secretions

Question 3

Where does acne tend to affect? Why?

What must be present for a diagnosis to be made?

Answer 3

• Acne affects areas of the body with a high density of pilosebaceous glands such as the face, chest and back. Clinical features vary widely depending on severity and the person affected.
• Comedones must be present for a diagnosis of acne to be made — if not present other diagnoses should be considered.

Question 4

What types of inflammatory lesions can be present in acne vulgaris?

Answer 4

Inflammatory lesions such as:

• Papules and pustules – superficial raised lesions (less than 5 mm in diameter).
• Nodules or cysts (larger than 5mm in diameter) – deeper, palpable lesions which are often painful and may be fluctuant. In very severe acne nodules may track together and form sinuses (acne conglobata).

Question 5

Which 5 pieces of lifestyle advice should be given to patients with acne vulgaris before any medical therapy?

Answer 5

1. To avoid over cleaning the skin (which may cause dryness and irritation). Acne is not caused by poor hygiene and twice daily washing with a gentle soap and fragrance-free cleanser is adequate.
2. If make-up, cleansers and/or emollients are used, non-comedogenic preparations with a pH close to the skin are recommended.
3. To avoid picking and squeezing spots which may increase the risk of scarring.
4. That treatments are effective but take time to work (usually up to 8 weeks) and may irritate the skin, especially at the start of treatment.
5. To maintain a healthy diet.

Question 6

What are the 3 options for first line therapy of mild-moderate acne vulgaris?

Answer 6

• A topical retinoid (for example adapalene [if not contraindicated]) alone or in combination with benzoyl peroxide. Retinoids are contraindicated in pregnancy and breastfeeding.
• A topical antibiotic (for example clindamycin 1%) — antibiotics should always be prescribed in combination with benzoyl peroxide to prevent development of bacterial resistance. Topical benzoyl peroxide and topical erythromycin are usually considered safe in pregnancy if treatment is felt to be necessary.
• Azelaic acid 20%.

Question 7

What is the MOA of retinoids?

Answer 7

Retinoids act to normalize desquamation by reducing keratinocyte proliferation and promoting differentiation. Topical retinoids also block several important inflammatory pathways that are activated in acne: Toll-like receptors, leukocyte migration, and the AP-1 pathway

Question 8

What is the second line therapy if topical therapy fails in acne vulgaris?

Answer 8

If response to topical preparations alone is inadequate consider adding an oral antibiotic such as lymecycline or doxycycline (for a maximum of 3 months).

Question 9

What is the definition of acne rosacea?

Answer 9

Acne rosacea is a chronic relapsing skin condition affecting the face, characterized by recurrent episodes of facial flushing, erythema, telangiectasia, papules and pustules. There may be eye symptoms (ocular rosacea), which are usually bilateral.

Question 10

What are the 4 types of acne rosacea?

Answer 10

• erythematotelangiectatic
• papulopustular
• phymatous
• ocular

Question 11

What are the features of the typical patient? Who gets the most severe acne rosacea?

Answer 11

Typically, it first presents between the ages of 30–50 years in people who are fair-skinned. Although it is more common in women, it tends to be more severe in men

Question 12

Give 5 triggers for acne rosacea.

Answer 12

• temperature
• sunlight
• strenuous exercise
• stress, spicy foods
• alcohol
• hot drinks

Question 13

Diagnosis of acne rosacea is clinical and depends on the presence of one or more clinical features. What are these(6)?

Answer 13

1. Flushing or transient erythema (pre-rosacea).
2. Persistent erythema (erythematotelangiectatic rosacea).
3. Telangiectasia (erythematotelangiectatic rosacea).
4. Papules and pustules (papulopustular rosacea).
5. Phymatous changes (phymatous rosacea), most commonly rhinophyma.
6. Ocular symptoms (ocular rosacea), such as red, gritty, dry or irritated eyes, and the person may describe a foreign body sensation in the eyes.

Question 14

What are the first line options for mild-moderate and moderate-severe acne rosacea?

Answer 14

For mild or moderate papulopustular rosacea, treatment options include topical metronidazole or topical azelaic acid.

For moderate to severe papulopustular rosacea, an oral tetracycline or erythromycin is recommended.

Question 15

What is the definition of psoriasis?

Answer 15

Psoriasis is a systemic, t-cell immune-mediated, inflammatory skin disease which typically has a chronic relapsing-remitting course, and may have nail and joint (psoriatic arthritis) involvement. Psoriasis is a chronic inflammatory skin condition characterised by clearly defined, red and scaly plaques (thickened skin).

Chronic plaque psoriasis (including scalp psoriasis, flexural psoriasis, and facial psoriasis) is the most common form, affecting 80–90% of people with psoriasis. The second most common form is localized pustular psoriasis of the palms and soles. Other forms of psoriasis include:

• Guttate psoriasis.
• Nail psoriasis.
• Erythrodermic and generalized pustular psoriasis (rare medical emergencies, may be life-threatening).

Question 16

Give 5 risk factors associated with onset or exacerbation of psoriasis.

Answer 16

1. infection
2. drugs (including corticosteroid withdrawal)
3. ultraviolet light exposure
4. trauma
5. hormonal changes
6. stress
7. smoking
8. alcohol.

Question 17

The diagnosis of psoriasis is usually based on clinical findings. Features suggesting psoriasis include(4)?

Answer 17

1. Distribution — psoriasis often occurs on extensor surfaces (elbows and knees), trunk, flexures, sacral and natal cleft, scalp and behind the ears, and umbilicus.
2. Size and shape of lesions — there is usually a clear delineation between normal and affected skin.
3. Colour — may be pink or red, but in people with pigmented skin this may not be obvious. Scale is typically silvery in colour.
4. Involvement of other areas — such as the joints or nails.

Question 18

Give the 8 types of psoriasis.

Answer 18

1. Pustular psoriasis.
2. Erythrodermic psoriasis.
3. Chronic plaque psoriasis.
4. Scalp psoriasis.
5. Facial psoriasis.
6. Flexural psoriasis.
7. Guttate psoriasis.
8. Nail psoriasis.

Question 19

What is the first line therapy for trunk and limb psoriasis in an adult?

Answer 19

Offer a potent corticosteroid applied once daily plus vitamin D or a vitamin D analogue applied once daily (applied separately, one in the morning and the other in the evening) for up to 4 weeks as initial treatment for adults with trunk or limb psoriasis.

Question 20

If first line psoriasis management is not effective, then what is tried?

Answer 20

If once-daily application of a potent corticosteroid plus once-daily application of vitamin D or a vitamin D analogue does not result in clearance, near clearance or satisfactory control of trunk or limb psoriasis in adults after a maximum of 8 weeks, offer vitamin D or a vitamin D analogue alone applied twice daily.

Question 21

What is the third line management of psoriasis?

Answer 21

If twice-daily application of vitamin D or a vitamin D analogue does not result in clearance, near clearance or satisfactory control of trunk or limb psoriasis in adults after 8–12 weeks offer either:

• a potent corticosteroid applied twice daily for up to 4 weeks or
• a coal tar preparation applied once or twice daily.

Question 22

What 3 therapies can be considered if a psoriatic patient does not respond to topical therapies?

Answer 22

• UV phototherapy
• Biologics anti-TNF
• Systemic treatments- methotrexate, ciclosporin

Question 23

What is this?

Answer 23

Psoriasis

Question 24

What is the definition of cellulitis?

Answer 24

Cellulitis is a common bacterial infection of the lower dermis and subcutaneous tissue. It results in a localised area of red, painful, swollen skin, and systemic symptoms. Similar symptoms are experienced with the more superficial infection, erysipelas, so cellulitis and erysipelas are often considered together.

Question 25

What are the most common causative organisms of cellulitis?

Answer 25

Cellulitis develops when microorganisms (most commonly Streptococcus pyogenes and Staphylococcus aureus) gain entry to the dermal and subcutaneous tissues via disruptions in the cutaneous barrier.

Question 26

Name 5 risk factors for developing cellulitis?

Answer 26

1. Obesity
2. Skin fissuring
3. Diabetes
4. Venous disease
5. Pregnancy
6. Alcoholism

Question 27

What is a rare cause of cellulitis which is most commonly seen in puncture wounds to the hand and foot?

Answer 27

Pseudomonas aeruginosa

Question 28

What is often the first sign of cellulitis?

Answer 28

The first sign of the illness is often feeling unwell, with fever, chills and shakes (rigors). This is due to bacteria in the blood stream (bacteraemia).

Question 29

Systemic symptoms are soon followed by development of a localised area of painful, red, swollen skin. Other signs include(6)?

Answer 29

1. Dimpled skin (peau d’orange)
2. Warmth
3. Blistering
4. Erosions and ulceration
5. Abscess formation
6. Purpura: petechiae, ecchymoses, or haemorrhagic bullae

Question 30

What are the 5 most serious complications of cellulitis?

Answer 30

1. Necrotising fasciitis (a more serious soft tissue infection recognised by severe pain, skin pallor, loss of sensation, purpura, ulceration and necrosis)
2. Gas gangrene
3. Severe sepsis (blood poisoning)
4. Infection of other organs, eg pneumonia, osteomyelitis, meningitis
5. Endocarditis (heart valve infection).

Question 31

What is the management of cellulitis?

Answer 31

• If severe enough, hospital admission and IV ABx
• If not so severe, oral ABx

Question 32

What is the definition of scabies?

Answer 32

Scabies is an intensely itchy skin infestation caused by the human parasite Sarcoptes scabiei. A person with scabies has an average of 10–15 mites.

Question 33

What is the definition of crusted scabies?

Answer 33

Crusted scabies is a hyperinfestation with thousands or millions of mites present in exfoliating scales of skin. It develops as a result of an attenuated immune response by the host.

Question 34

What are the clinical features of scabies(3)?

Answer 34

1. Itch
2. Burrows
3. Generalised rash
   4.

Question 35

What 3 investigations can aid with the diagnosis of scabies?

Answer 35

The clinical suspicion of scabies in a patient with an itchy rash, especially when reporting itchy household members, can be confirmed by:

1. Dermatoscopy: the mite at the end of a burrow has characteristic jet-plane or hang-glider appearance
2. Microscopic examination of the contents of a burrow
3. Skin biopsy: this may reveal characteristic scabies histopathology, but this is often negative or nonspecific, eg if taken from the inflammatory rash rather than the surface of a burrow.

Question 36

What is the first and second line medical therapy for scabies? What home step can patients with scabies take?

Answer 36

• For children over the age of two months, and adults with non-crusted scabies, prescribe a topical insecticide. Permethrin 5% cream is first-line treatment, with malathion aqueous 0.5% if permethrin is contraindicated or not tolerated (such as in people with allergy to chrysanthemum).
• A second application is required one week after the first.
• Their bedding, clothing, and towels (and those of all potentially infested contacts) should be decontaminated by washing at a high temperature (at least 60°C) and drying in a hot dryer, or dry-cleaning, or by sealing in a plastic bag for at least 72 hours.

Question 37

What is the definition of impetigo? What are the two main types?

Answer 37

Impetigo is a common superficial bacterial infection of the skin. The two main clinical forms are:

1. Non-bullous impetigo — accounts for the majority of cases (about 70%).
2. Bullous impetigo — bullae are fluid filled lesions which are usually more than 5mm in diameter.

Impetigo can develop as a primary infection in otherwise healthy skin or as a secondary complication of pre-existing skin conditions such as eczema, scabies, or chickenpox.

Question 38

What is the cause of impetigo?

Answer 38

Transmission of impetigo occurs directly through close contact with an infected person or indirectly via contaminated objects such as toys, clothing, or towels.

Bacteria enter the skin through breaks caused by minor trauma (such as insect bites or scratches) or underlying skin conditions (such as eczema or scabies).

Question 39

What are the causative agents of bullous and nonbullous impetigo?

Answer 39

Non-bullous impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes or a combination of both.

Bullous impetigo is caused by Staphylococcus aureus.

Question 40

What are the clinical features of non-bullous impetigo?

Answer 40

Lesions begin as thin walled vesicles or pustules (seldom seen on clinical examination as they rupture quickly) which release exudate forming a characteristic golden/brown crust. Once crusts have dried they separate leaving mild erythema which then fades — healing occurs spontaneously without scarring within 2-3 weeks.

The course may be more prolonged in people with pre-existing skin conditions (such as eczema or scabies) or in hot/humid climates.

Lesions can develop anywhere on the body but are most common on exposed skin on the face (in particular the peri-oral and peri-nasal areas), limbs and flexures (such as the axillae).

Question 41

What are the clinical features of bullous impetigo?

Answer 41

• Lesions appear as flaccid fluid filled vesicles and blisters (often with a diameter of 1-2cm) which can persist for 2-3 days. Blisters rupture leaving a thin flat yellow/brown crust. Healing usually occurs within 2-3 weeks without scarring.
• Lesions can occur anywhere on the body but are most common on the flexures, face, trunk and limbs.
• Bullous impetigo may be particularly widespread in infants.
• Systemic features may occur if large areas of skin are affected and include fever, lymphadenopathy, diarrhoea and weakness.

Question 42

What is the recommended first line treatment for mild impetigo and widespread impetigo?

Answer 42

If infection is mild and very localized,

• treat with topical fusidic acid (three times a day for 5 days).

If impetigo is more widespread or bullous treat with an oral antibiotic:

• Oral flucloxicillin (or clarithromycin) (four times a day for 7 days) is recommended first line

Question 43

What is the definition of folliculitis?

Answer 43

Folliculitis is the name given to a group of skin conditions in which there are inflamed hair follicles. The result is a tender red spot, often with a surface pustule.

Folliculitis may be superficial or deep. It can affect anywhere there are hairs, including chest, back, buttocks, arms and legs. Acne and its variants are also types of folliculitis.

Question 44

What is the definition of a viral wart?

Answer 44

Cutaneous warts are small, rough growths which are caused by infection of keratinocytes with certain strains of the human papilloma virus (HPV). They can appear anywhere on the skin but are most commonly seen on the hands and feet

Question 45

What are the 3 types of cutaneous warts?

Answer 45

1. Common wart (Verruca vulgaris).
2. Flat wart or plane wart (Verruca plana).
3. Plantar wart — wart on the sole of the foot (Verruca plantaris).

Question 46

Treatment of viral warts is not usually recommended. However, what 2 options are available to patients that insist?

Answer 46

1. Cryotherapy requires several treatments, can be painful at the time of application, and may cause pain, blistering, infection, scarring, and depigmentation.
2. Topical salicylic acid may require administration for up to 12 weeks and can cause local skin irritation.

Question 47

How many types of herpes simplex virus are there and what are they associated with?

Answer 47

Type 1 HSV is mainly associated with oral and facial infections

Type 2 HSV is mainly associated with genital and rectal infections

Question 48

Why is herpes simplex a chronic condition?

Answer 48

After the primary episode of infection, HSV resides in a latent state in spinal dorsal root nerves that supply sensation to the skin. During a recurrence, the virus follows the nerves onto the skin or mucous membranes, where it multiplies, causing the clinical lesion. After each attack and lifelong, it enters the resting state.

Question 49

What are the symptoms of type 1 HSV gingivostomatitis?

Answer 49

Primary Type 1 HSV most often presents as gingivostomatitis, in children between 1 and 5 years of age. Symptoms include fever, which may be high, restlessness and excessive dribbling. Drinking and eating are painful, and the breath is foul. The gums are swollen and red and bleed easily. Whitish vesicles evolve to yellowish ulcers on the tongue, throat, palate and inside the cheeks. Local lymph glands are enlarged and tender.

Question 50

What are the most common type 2 HSV symptoms in type 2 HSV?

Answer 50

Primary Type 2 HSV usually presents as genital herpes after the onset of sexual activity. Painful vesicles, ulcers, redness and swelling last for 2 to 3 weeks, if untreated, and are often accompanied by fever and tender inguinal lymphadenopathy.

In males, herpes most often affects the glans, foreskin and shaft of the penis. Anal herpes is more common in males who have sex with men than with heterosexual partners.

In females, herpes most often arises on the vulva and in the vagina. It is often painful or difficult to pass urine. Infection of the cervix may progress to severe ulceration.

Question 51

How is herpes simplex diagnosed?

Answer 51

If there is clinical doubt, HSV can be confirmed by culture or PCR of a viral swab taken from fresh vesicles. HSV serology is not very informative, as it’s positive in most individuals and thus not specific for the lesion with which they present.

Question 52

What is the treatment for herpes simplex?

Answer 52

Mild, uncomplicated eruptions of herpes simplex require no treatment. Blisters may be covered if desired, for example with a hydrocolloid patch. Severe infection may require treatment with an antiviral agent.

Antiviral drugs used for herpes simplex and their usual doses are:

• Aciclovir – 200 mg 5 times daily for five days

Question 53

What is the definition of herpes zoster infection?

Answer 53

Herpes zoster is a localised, blistering and painful rash caused by reactivation of varicella-zoster virus (VZV). Herpes zoster is characterised by dermatomal distribution, that is the blisters are confined to the cutaneous distribution of one or two adjacent sensory nerves. This is usually unilateral, with a sharp cut-off at the anterior and posterior midlines.

Herpes zoster is also called shingles.

Question 54

What are the symptoms of herpes zoster?

Answer 54

The first sign of herpes zoster is usually pain, which may be severe, relating to one or more sensory nerves. The pain may be just in one spot, or it may spread out. The patient usually feels quite unwell with fever and headache. The lymph nodes draining the affected area are often enlarged and tender.

Within one to three days of the onset of pain, a blistering rash appears in the painful area of skin. It starts as a crop of red papules. New lesions continue to erupt for several days within the distribution of the affected nerve, each blistering or becoming pustular then crusting over.

Question 55

What is the treatment for herpes zoster?

Answer 55

Antiviral agents

Question 56

What is the definition of candidiasis?

Answer 56

Candida is a yeast-like fungus which is part of the normal commensal flora of the human gastrointestinal tract and the vagina (in 13% of women)

It is not part of the normal skin flora, but there may be transient colonization of fingers or body folds.

Colonization with Candida is usually asymptomatic. However, where mucosal barriers are disrupted or if the host’s defences are lowered, it can cause infections (candidiasis) ranging from non-life threatening superficial mucocutaneous disorders to invasive disseminated disease involving multiple organs

Question 57

What are the 5 clinical features which aid a candidiasis diagnosis?

Answer 57

1. Soreness and itching is usual.
2. Thin-walled pustules with a red base may be present.
3. Scales may accumulate, producing a white-yellow, curd-like substance over the infected area.
4. In flexural areas (intertrigo), the skin fold is typically red and moist. As the condition develops, a typical fringed, irregular edge and pustular or papular satellite lesions may be present.
5. If the web spaces of the toes or fingers are involved, marked maceration with a thick, horny layer is usually prominent

Question 58

WHat is the first line therapy in adults and children with candidiasis?

Answer 58

• If the infection is not widespread and the person is not significantly immunocompromised, prescribe a topical antifungal treatment.
• For an adult, prescribe a topical imidazole (clotrimazole, econazole, miconazole, or ketoconazole) or terbinafine.
• For a child, prescribe topical clotrimazole, econazole, or miconazole.

Question 59

What is the second line therapy for candidiasis in adults and children?

Answer 59

For adults and children aged 16 years and older, treat with oral fluconazole 50 mg a day for 2 weeks then review response to treatment.

For children younger than 16 years of age, or if fluconazole is contraindicated, seek specialist advice.

Question 60

What is this?

Answer 60

Candidiasis

Question 61

What is the definition of foot dermatophyte infection?

Answer 61

Fungal infection of the foot is also known as ‘athlete’s foot’ or ‘tinea pedis’, and it describes superficial skin infection of the feet and toes, predominantly caused by dermatophytes.

Question 62

Name one causative organism of tinea pedis

Answer 62

1. Trichophyton (T.) rubrum
2. T. interdigitale, previously called T. mentagrophytes var. interdigitale
3. Epidermophyton floccosum

Question 63

Name 3 therapies for dermatophyte infection

Answer 63

1. Clotrimazole
2. Econazole
3. Efinaconazole
4. Ketoconazole

Question 64

What is the definition of atopic eczema?

Answer 64

• Atopic eczema (also known as atopic dermatitis) is a chronic, itchy, inflammatory skin condition that affects people of all ages, although it presents most frequently in childhood.
• It is typically an episodic disease of flares (exacerbations, which may occur as frequently as two or three times each month) and remissions; in severe cases, disease activity may be continuous.
• The term ‘atopic’ is used to describe a group of conditions (eczema, asthma, hay-fever, and food allergy) that are linked by an increased activity of the allergy component of the immune system

Question 65

Eczema can be categorised into two main types. What are these? And what types of eczema make them up?

Answer 65

• Exogenous eczema = Photosensitive eczema and Contact dermatitis
• Endogenous eczema = Atopic, Seborrheic, Discoid, Venous, Pompholyx and Asteatotic forms.

Question 66

What are the criteria for a diagnosis of atopic eczema?

Answer 66

An itchy skin condition (or parental report of scratching) plus three or more of the following:

1. Visible flexural eczema involving the skin creases, such as the bends of the elbows or behind the knees (or visible eczema on the cheeks and/or extensor areas in children aged 18 months or younger).
2. Personal history of flexural eczema (or eczema on the cheeks and/or extensor areas in children aged 18 months or younger).
3. Personal history of dry skin in the last 12 months.
4. Personal history of asthma or allergic rhinitis (or history of atopic disease in a first-degree relative of a child aged under 4 years).
5. Onset of signs and symptoms before the age of 2 years (this criterion should not be used in children younger than 4 years of age).

Question 67

What is the treatment for mild eczema?

Answer 67

Prescribe generous amounts of emollients, and advise frequent and liberal use.

Consider prescribing a mild topical corticosteroid (such as hydrocortisone 1%) for areas of red skin. Treatment should be continued for 48 hours after the flare has been controlled.

Question 68

What is the treatment for moderate eczema?

Answer 68

Prescribe a generous amount of emollients, and advise frequent and liberal use (more than usual). For more information on emollients, including available products and usage instructions, see the prescribing information section on Emollients.

If the skin is inflamed, prescribe a moderately potent topical corticosteroid (for example betamethasone valerate 0.025% or clobetasone butyrate 0.05%) to be used on inflamed areas. Treatment should be continued for 48 hours after the flare has been controlled.

For delicate areas of skin (such as the face and flexures), consider starting with a mild potency topical corticosteroid (such as hydrocortisone 1%) and increase to a moderate potency corticosteroid only if necessary. Aim for a maximum of 5 days’ use.

Question 69

What is the treatment for severe eczema?

Answer 69

Prescribe a generous amount of emollients and advise frequent and liberal use (more than usual). For more information on emollients, including available products and usage instructions, see the prescribing information section on Emollients.

If the skin is inflamed, prescribe a potent topical corticosteroid (for example betamethasone valerate 0.1%) to be used on inflamed areas.

For delicate areas of skin such as the face and flexures, use a moderate potency corticosteroid (such as betamethasone valerate 0.025% or clobetasone butyrate 0.05%). Aim for a maximum of 5 days’ use.