Dermatology Pt1 Flashcards
Average thickness & weight of skin?
1-2mm & 4-5kg
How often are skin cells replaced?
Every 28 days
Three layers that makes up the skin?
Epidermis (outer)
Dermis (middle)
Subcutaneous (innermost, fat cells)
5 functions of the skin
Waterproof barrier
Temperature regulation
Protection
Vit D synthesis
Sensitivity
What characterises acne?
The formation of comedones (blackheads & whiteheads)
& formation of spots (papules & pustules)
What is the overall cause of acne?
Inflammation of the pilosebaceous units of the skin
Specific causes of acne
- Rise in sebum secretion from sebaceous glands in response to production of sex hormones in adolescence
- Overgrowth of bacteria in follicular duct which utilises excess sebum as nutrient source
- Bacterial ‘plug’ resulting in partial blockage of follicle
- Inflammation caused by body’s immune response
Four skin changes by acne? Formation of…
- Open comedones - blackheads
- Closed comedones - whiteheads
- Papules - red-coloured bumps
- Pustules - white/yellow pus-filled spots
Which hormone is the pilosebaceous gland more sensitive to and what is the outcome of this?
Testosterone. Increase in T leads to higher oil production, encouraging bacterial overgrowth at follicle.
Two classes of acne
- Non-inflammatory (comedonal)
- Inflammatory (non-comedonal) - papules / pustules / nodules
Severity classes of acne
- Mild - comedones & papules/pustules
- Moderate - papules, pustules, and nodules
- Scarring nodulocystic acne or fulminans
External causes of acne (3)
- Chloracne caused by certain chlorine-containing industrial chemicals
- Drug-induced acne, drugs related to sex hormones (e.g. steroids)
- Cosmetic acne caused by cosmetic products
What are the four purposes of acne treatment?
- Reduce sebum secretion
- Prevent blockage of the pilosebaceous duct
- Reduce or eliminate colonisation of bacteria
- Reduce inflammation
What are the treatment options for the different severities of acne?
Topical - creams/gels for mild & moderate
Oral medication - severe
Four topical therapies
- Benzoyl peroxide
- Retinoids
- Comedolytics & keratolytics
- Topical antibiotics
How does benzoyl peroxide reduce acne?
Works as an antiseptic to reduce number of P. acnes and helps clear pores
Retinoids
Reduce sebum production & inflammation. Inhibit growth of P. acnes
2 examples of retinoids
- Tretinoin
- Isotretinoin
Comedolytics & keratolytics
Reduces skin’s ability to produce comedones, softening hard keratin and slowing shedding of skin
Topical antibiotics examples (2)
Anti-inflammatory & used in conjunction with previously mentioned treatments. Erythromycin & clindamycin.
Three most common oral treatments for severe acne?
- Oral antibiotics
- Hormonal therapy
- Oral retinoids
What is a concern with oral antibiotics?
Bacterial resistance
Examples or oral antibiotics (5)
Tetracycline
Oxytetracycline
Doxycycline
Lymecycline
Erythromycin
Two examples of hormonal therapy and why are they used?
Oral contraceptive pill & co-cyprindiol. Used to lower testosterone in the body. Both pills contain an oestrogen and either a progesteron or anti-androgen
Example of retinoid used & common side effects
Isotretinoin
dry lips, nosebleeds, hair loss, mood changes, and liver damage
Where does Rosacea (chronic skin condition) affect?
Face
Common symptoms & which population does Rosacea typically affect?
Facial flushing, thickened, bumpy skin and eye symptoms. Middle-aged women between 30-60yrs old.
How many types of Rosacea are there?
4
Triggers of Rosacea which can make the condition worse:
Exact cause is unknown.
Exposure to sunlight
Stress
Exercise
Cold weather (wind)
Heat
Menopause
Hot drinks, alcohol, and caffeine, spicy foods
For mild Rosacea, what treatments are used?
Topical treatments
Antibioitcs - metronidazole / sodium sulfacetammide to treat pustules
Comedolytic agents - azelaic acid to unblock pores & reduce inflammation
For moderate to severe Rosacea, what treatments are used?
Oral treatments
Antibiotics - tetracyclines or erythromycin
Retinoids - isotretinoin
What are some causes of dermatitis? (3)
Irritants
Allergens
The body’s own immune system
Two ways of classing dermatitis?
By cause & by duration of episode (chronic or acute)
What is a common sign on a cellular level that it is acute?
Fluid accumulation within the dermis, leading to separation of the layers and blistering
What is a common sign on a cellular level that it is chronic?
Skin is thickened rather than blistered
In both acute & chronice dermititis, inflammatory cells are attracted to the area to exacerbate the condition
When a causative agent is external like an irritant chemical, they cause an immediate response or cumulative response (with weaker chemicals for repeated exposure), what is the first step towards irritation from these?
They wear away the protective oily film on the surface of the skin
Next, what causes the irritation?
Chemicals can now penetrate the keratinous part of the skin, and trigger an inflammatory immune response within the cells of the dermis.
The rash tends to be localised to the area of exposure and may be erythematous (reddened), itchy, inflamed, or swollen, what does more prolonged exposure give rise to?
Cracked, irritable, thickened, scaly skin.
Common parts of the skin in contact?
Face and hands of workers in certain industries
e.g. car mechanics, hairdressers, textile workers
Two common exogenous types of contact dermatitis
Irritant (chemical) & Allergic (allergen)
Four stages of the development of allergic dermatitis:
- An allergen enters the skin and encounters Langerhans cells - these are found scattered within the epidermis
- These take up the allergen which pass on the identification to T-cells
- T-cells multiply, circulate, then accumulate at site of reaction
- If allergen is still detected, T-cells are activated and respond by releasing a variety of inflammatory molecules = redness, swelling, and inflammation
How long does it take until the rash develops typically?
After 24hrs to the exposure. Can take less time.
Initial symptoms/stages of allergic dermatitis:
Erythematous, inflamed area around the exposure site, often with small vesicles
Prolonged exposure to the allergen:
Skin thickens, fissured (cracked), and dry
More prolonged exposure:
Rash may start to spread to areas of skin not in direct contact with the allergen
What is a method of determining the allergen causing the inflammation and to help prevent further outbreaks of allergic contact dermatitis (ACD)?
Patch-testing
What is the most common form of eczema?
Atopic eczema. 20% of children, 10% of adults. Chronic condition. About 60% of those who develop it do so before the age of 1.
Where does the rash start usually in infants and then progress to (common sites)?
Face & hands. Then, to wrists & ankles, the areas behind the knees and in front of the elbow (flexor surfaces).
Atopic eczema is associated with which gene?
Filaggrin gene. Linked to asthma & rhinitis.
What types of food can be the root cause of atopic eczema?
Cows milk, egg white, tomatoes, oranges, lemons, chocolate, or nuts.
What causes infantile seborrhoea (seborrhoeic eczema) and where is it usually?
Overactive sebaceous glands resulting in oily skin. Nappy area or head and can rapidly spread.
What is unique about it and how should it be treated if secondary infection is suspected?
Baby is not unwell (not itchy/sore). Keratinolytic topical treatment can be used to improve appearances.
Where does adult seborrhoeic eczema tend to affect the most?
Where most of the sebaceous glands are but sebum secretion appears to be normal (face, scalp, and chest)
Cause?
Appear to be genetic and endogenous factors involved which permit an excessive growth of a yeast
How can it be treated?
Medicated shampoos or preparations available on prescription that contain anti-fungal medicines
Where does gravitational eczema (varicose eczema) affect and for which population?
Lower legs in mainly middle-aged & elderly people
What causes gravitational eczema?
Underlying disease of the vein valves which causes increased pressure = leakage of fluid into the skin, reddish-brown pigmentation, itching & blistering.
What happens to the skin as a result of this & treatments?
Skin thins and becomes fragile with an increased risk of ulceration.
Treatments are moisturising creams with/without a mild steroid, plus compression bandaging where appropriate.
Who is typically affected by discoid eczema?
Adults with very dry skin
What is the appearance of discoid eczema?
Circular rings of very itchy red lesions on the limbs or as small pustules - sometimes on the hands.
What happens to these lesions after a few days?
Lesions weep, become crusted and may become infected. Later, they become scaly and dry up, leaving a flaky patch of skin.
Where is pompholyx eczema restricted to and what is it characterised by?
Restricted to the hands & feet and is characterised by blistering. Blisters often weep, break and itch.
Who does asteatotic eczema typically affect and what usually characterises it?
Elderly people in the lower legs, but occasionally upper arms, thighs, and lower back. Appears dry and a little rough, but then develops a distinctive banded pattern often with cracking.
Cause is unknown, but what is it linked with?
Connected with a loss of skin oils, a dry atmosphere, hot baths & vigorous towel drying.
What are the treatment options available for dermatitis (eczema)? (5)
Emollients
Topical corticosteroids
Antibiotics & antimicrobials
Antipruritics
Immunosuppressants
Emollients:
Creams, lotions or gels to keep the skin moist and supple. Restore barrier function of the skin, keeping moisture, infection and irritants from penetrating the superficial layers of the skin.
Topical corticosteroids:
Reduce inflammation in the skin rapidly
Different potencies (4):
Mild - hydrocortisone cream
Moderate - clobetasone, betamethasone diproprionate ready diluted
Potent - betamethasone diproprionate
Very potent - clobetasol propionate
What can prolonged use of topical corticosteroids do?
Thin the skin
Antibiotics & antimicrobials:
Used when dermatitis becomes infected taken either orally or topically. Fusidic acid & erythromycin is commonly used topically, either alone or in preparation with a steroid.
Antipruritics:
Help reduce itching and break the ‘itch-scratch’ cycle (drugs inhibiting itching). Physical measures in place like shortened nails & wet-wrap bandaging of affected areas may help.
Examples of topical antipruritic & oral antipruritic:
Crotamiton - topical
Antihistamines - oral
Topical immunosuppressants & why:
Pimecrolimus & tacrolimus used to help keep eczema suppressed on a long-term basis.
How does Pimecrolimus work?
Blocks T-cell activation and reduced activation of cytokines
What is psoriasis and its characterisation?
Psoriasis is a chronic, autoimmune inflammatory skin condition, characterised by inflamed, thickened
areas of skin
Most obvious symptom of psoriasis?
Flaky lesions on the skin or in the hair - sometimes when the flakes are scratched off, small blood droplets appear (Auspitz’s sign)
Psoriasis can develop at the site of an injury or scarring after surgery. Some medicines are known to trigger or aggravate the condition, as can stress.
How do the skin lesions of psoriasis form? (2)
- Increased number of cells in the basal layer which divide 20 times faster than in normal skin
- Causes new skin cells to rise to the surface of the epidermis much more quickly than during normal skin cell division
- Small blood vessels begin to develop causing this extra tissue to build up into raised thickened plaques
Why does the skin have a silvery & flaky appearance?
A thick layer of immature keratinocytes hides under the underlying colour of the skin
What % of the UK population have psoriasis?
2%
Which two periods in life is the risk of developing psoriasis the greatest?
- During teenage years into twenties
- Sixties
Most common form of psoriasis and where does it affect the body the most?
Plaque psoriasis. Knees, elbows, lower back or scalp.
What is meant by the lesions appearing symmetrical nearly always?
The red patches with silvery, scaly surfaces tend to occur on both sides of the body in similar places.
5 other forms of psoriasis:
- Guttate
- Flexural
- Palmoplantar
- Erythrodermic
- Scalp
Guttate psoriasis:
Lesions are rash-like and appear suddenly on the trunk and/or limbs. This form is most common in adolescents or young adults and may follow a streptococcal throat infection.
Flexural psoriasis
Lesions are smooth and often have a glazed appearance appearing under the arms, in the groin, in the folds of the breasts in women and in the cleft of the buttocks.
Palmoplantar psoriasis:
Characterised by sterile pustules on the palms of the hands or soles of the feet
Erythrodermic psoriasis
A serious condition in which the entire skin is inflamed.
Scalp psoriasis:
The scalp may be dry and flaky or, in more severe disease, red and inflamed. The scalp may be the only site, but up to 50% of people with chronic plaque psoriasis can have scalp lesions. Temporary hair loss
may occur.
NICE = National Institute for Health & Care Excellence
What do NICE recommend as the first line of treatment?
Topical therapy
What happens if the topical therapy is considered unlikely to control psoriasis?
After specialist referral, phototherapy or systemic therapy should be added
There are many typical treatments. Firstly, emollients & tar preparations:
Emollients - creams, ointments, lotions, which help soften and moisturise the skin to reduce cracking, inflammation, and pain
Tar preparations - impregnated bandages and dressings. Coal tar thought to inhibit DNA synthesis, reducing rate of cell division
Corticosteroids & Vit D analogues:
Corticosteroids - useful for treating inflamed, stubborn plaques on the body, examples include hydrocortisone, clobetasone, betamethasone dipropionate and clobetasol propionate
Vit D analogues - topical preparations able to control the rate of cell division and formation of excess keratinocytes. Examples include calcipotriol & calcitriol
Combination treatment & Phototherapy:
Combination treatment - a topical preparation containing both Vit D derivative and steroid in one formulation. UK usually uses Dovobet
Phototherapy - narrow band UVB or and UVA can be used to slow growth of affected skin cells (wavelengths of UV). Psoralen used to prime skin prior to UVA treatment, so it is known as PUVA.
The retinoids & Dithranol:
Retinoids - Topical or oral form. They reduce inflammatory changes in the skin and change the rate of turnover of keratinocytes. Oral preparations can cause side effects such as dry skin, mood disorders including depression, nosebleeds and liver dysfunction. They are also teratogenic, and so adequate contraception must be used in women of childbearing age. Examples include acitretin (oral) and tazarotine (topical).
Dithranol - Applied to lesions as a paste to block cell division. Time-consuming, stains, messy, but effective when used with a daily tar bath and UVB therapy. Applied for 30 mins then washed off.
Teratogenic = relating to defects to an embryo or foetus
Immunosuppressants & Biologic agents
Immunosuppressants - methotrexate can slow cell division and is valuable in severe and refractory psoriasis.
Biologic agents - an important advance for moderate to severe psoriasis, including psoriatic arthritis. They reduce inflammation by targeting specific overactive cells or chemicals in the immune system. Common targets of TNF-α, IL-12 and IL-23. Examples include etanercept, adalimumab, ustekinumab and secukinumab. Golimumab can be used as a third-line therapy for patients with severe psoriatic arthritis who have not responded to other therapies. Hydroxycarbamide may also sometimes be used orally to treat severe psoriasis. This works by slowing down the rapid division of skin cells.
Usually psoriasis waxes and wanes. But, some patients have it chronically and are systemically unwell leading to admission. What treatments are they then given?
Oral corticosteroids - prednisolone and immunosuppressants like methotrexate
Skin growths and abnormal pigmentation may be present at birth or may develop during life. What are they usually in response to?
Sun exposure
What does sun exposure cause and what do these indicate?
Freckles and moles. They are indicative of damage caused by UV radiation from the sun.
Prolonged exposure of UV radiation from the sun leads to & how to protect yourself?
Skin cancer. Sunscreen, hat, and long sleeved clothing.
What are actinic keratoses and where are they found?
Areas of sun-damaged skin which can develop on areas of the body frequently exposed to sunlight. Usually found the arms, backs of hands, lower legs, and the scalp of balding men.
What is their appearance?
Skin-coloured, brown, pink, or red. Skin feels rough and dry, sometimes raised. Diameter of 1-2cm.
Why are they dangerous?
Approximately 20% of actinic keratoses transform into a form of skin cancer known as squamous cell carcinoma
Treatment of milder cases and smaller lesions for actinic keratoses:
Diclofenac cream
Severe cases to destroy abnormal cells: (5)
- Surgical removal
- Photodynamic therapy
- Laser treatment
- Freezing with liquid nitrogen
- Topical creams containing 5-fluorouracil
Two classes of skin cancer and the main cause for both:
Melanoma & non-melanoma. Excessive UV exposure.
Most common form of cancer in people aged 15-34?
Malignant melanoma
Where do melanomas usually begin begin as?
Skin as a mole or from normal looking skin
What are the four main types of skin melanoma?
Superficial spreading melanoma
Nodular melanoma
Lentigo maligna melanoma
Acral melanoma
Which is the most common type?
Superficial spreading melanoma
Where is superficial spreading melanoma most commonly found in males and for females?
Males - chest & back
Females - legs
Nodular melanoma fact & location:
Cells grow the fastest and found normally on the chest, back, head, or neck
Lentigo maligna melanoma location on skin:
Areas of skin with lots of sun exposure over many years
How does lentigo maligna melanoma initially develop?
Develops from a slow-growing precancerous condition called a lentigo maligna or Hutchison’s freckle which looks like a stain on the skin
Acral melanoma & its location & population:
Rarest type usually found on the palms of hands, soles of feet, or under nails. More common in people with black/brown skin and thought to be unrelated to sun exposure.
What is the first treatment for melanoma?
Early melanoma is treated with local surgery. If the cancer has not spread to the lymph nodes, no further treatment is required.
What happens if the melanoma returns?
Further surgery with chemo/radiotherapy is required. If spread is likely, further adjuvant immunotherapy alongside mAbs.
Where do non-melanoma skin cancers usually develop?
Epidermis. Usually named after the type of skin cell from which they develop.
Two most common non-melanoma skin cancers & their prevalence?
- Basal cell carcinoma (BCC) - 75%
- Squamous cell carcinoma (SCC) - 20%
BCC location on a cellular level and its appearance:
Basal cells found lining the bottom of the epidermis. Appears as a red or pink lump, or flat, flesh-coloured patches of skin, with rolled edges. 10-15mm diameter.
Facts about BCC in the early stage treatment & aggressive types: (3)
- Treated early-on, completely cured (mostly)
- Aggressive BCCs if left to grow can spread into deeper layers of the skin
- BCCs do not metastasise
Local recurrence meaning?
Small number of BCCs may come back in the same area of the skin after treatment.
Superficial BCC treatment alternative to surgery & locally invasive BCCs:
Superficial - topical imiquimod immunotherapy cream. This causes interferon production (cytokines)
Local - systemic chemo/radiotherapy to encourage local tumour shrinkage
What is an alternative treatment option, instead of surgery, for large but not too deep BCCs?
Photodynamic therapy (PDT)
How does PDT work?
PDT involves administering a cream containing 5-aminolaevulinic acid (ALA) which is absorbed into the cells. The skin is then exposed to light and the cells containing the ALA are destroyed.
Where does SCC originate and its appearance?
Squamous cells which line the top of the epidermis. SCC usually appears as firm red lumps, or a flat, scaly and crusted scab-like lesion that does not heal.
Where does SCC locate?
Often appears on the face, lips, ears, hands, arms and legs - areas of high sun exposure.
SCC growth rate and prognosis:
Slow-growing and only spread to other parts of the body if left untreated for a long time. Most people treated for SCC are completely cured with localised treatment.
SCC treatment and superficial SCC treatment:
Minor surgery
topical 5-fluorouracil chemotherapy cream can be used as an alternative to surgery.
Rare skin cancers (4):
- Cutaneous T-cell lymphoma (CTCL)
- Kaposi’s carcinoma
- Angiosarcoma
- Merckel cell carcinoma
Who is affected mostly by cutaneous T-cell carcinoma and what causes it?
Peoples aged between 40-60yrs old. More common in men than women. Caused by T cells in skin growing in an uncontrolled way. Develops very slowly.
Early & late-stage symptoms:
Early - looks like eczema or psoriasis with potentially one or more tumours on the skin with swollen lymph nodes in some patients
Late - large areas of skin are affected. Skin is very swollen, red, itchy, scaly, may be painful.
Treatments for CTCL in the early & advanced stage:
Early - topical steroid cream & topical chemotherapy, PUVA or radiotherapy
Advanced - systemic treatments like chemotherapy, retinoids, or biological therapies are used
Who does Karposi’s carcinoma typically affect and what virus causes it & its transmission?
Patients suffering from HIV. Rarely affects other people who are elderly men of Africa, Italian, and Jewish ancestry.
human herpes virus 8 (HHV8) through human bodily fluid
Not everybody who is infected with HHV8 contracts Karposi’s carcinoma, what is a factor which can play a part in its development?
Weakened immune system (HIV infection or patients taking immunosuppressant medications)
What does treatment depend upon and what are some options?
Cause of immunosuppression. Antiviral treatments in patients with HIV, or switching immunosuppressants. Radiotherapy & chemotherapy.
Cellular level & location & population for angiosarcoma
Inner lining of the blood vessels. Occurs in any area of the body in men & women of all races & ages. They are typically aggressive & fast-growing.
Which type of angiosarcoma makes up most of them?
Cutaneous angiosarcoma (skin) - found in scalp & face
Typical indications of angiosarcoma which may not necessarily come across as being potentially cancerous?
As a skin infection, bruise, a lesion that does not heal. May present itself as a soft lump that can be felt or seen.
Treatment for angiosarcoma:
Usually surgery with chemo/radiotherapy. Aggressiveness of angiosarcoma usually leads to metastasis and a poor prognosis.
Merckel cell carcinoma (neuroendocrine carcinoma) of the skin is caused by?
Merckel cells found in the epidermis growing uncontrollably.
Location of merckel cell carcinoma and feature:
On sun-exposed skin as a single lump that is fast-growing, painless, firm and dome-shaped or raised, red or violet in colour. Grows rapidly and metastasises early.
Treatment of merckel cell carcinoma:
Surgery & chemo/radiotherapy
