Introduction to Dermatology Flashcards
What adnexal structures are part of the skin?
Hair
Nails
Glands
Sensory structures
What are the layers of the skin?
Epidermis
Dermis
Subcutaneous tissue
What determines skin colour?
Melanin
What are the two types of melanin pigmentation?
Eumelanin
Phemelanin
In darker skin tones, is there more eumelanin or phemelanin?
Eumelanin
What are the three phases of the hair cycle?
Anagen
Catagen
Telogen
Anagen?
Active growing phase
80-90% of hair in this stage
Catagen?
2-3 week phase growth stops and the follicle shrinks
1-3% of hair
Telogen?
Resting phase for 1-4 months
UP to 10% of hair in a normal scalp
Functions of the skin?
Thermoregulation- insulation and heat transfer
Skin immune system
Barrier- protection but also keeps in water and electrolytes
Sensation
Interpersonal communication e.g. physical appearance, smell
What vitamin synthesis does the skin play a role in?
The synthesis of vitamin D
How does the skin have a role in vitamin D synthesis?
UV light converts 7-dehydrocholesterol to cholecalciferol
List some external causes of skin disease.
Temperature
UV light
Chemicals- allergen or irritant
Infection
Trauma
What are some of the internal causes of internal disease?
Systemic disease
Genetics
Drugs
Infection
Autoimmune conditions
What can cause skin photosensitivity?
Medications
->usually only exposed sites affected, often under the chin and behind ears are spared so worth checking is suspecting due to photosensitivty
Which types of light can cause photosensitivity?
UVA, UVB or visible light or a combination of these
List some skin conditions which can be caused for external causes.
Cold injury e.g. frostbite, chilblains
Skin necrosis
Cold urticaria
Which type of photosensitivity does suncream help with?
UVB photosensitivity
The following terms can be used to describe skin lesions.
Vesicle?
Small fluid filled lesions
The following terms can be used to describe skin lesions.
Bulla?
Large fluid filled lesion
The following terms can be used to describe skin lesions.
Pustule?
Small pus filled lesion
The following terms can be used to describe skin lesions.
Abscess?
Large pus filled lesion
The following terms can be used to describe skin lesions.
Erosion?
Loss of epidermis
The following terms can be used to describe skin lesions.
Ulcer?
Loss of epidermis and dermis
The following terms can be used to describe skin lesions.
Macule?
Non-palpable change in skin colour with distinct borders
The following terms can be used to describe skin lesions.
Palpule?
Palpable, solid lesion <1cm in diameter
The following terms can be used to describe skin lesions.
Plaque?
Palpable, solid lesion >1cm in diameter
The following terms can be used to describe skin lesions.
Nodule?
Palpable lesion >1cm in diameter which is taller than it is wide
What is the size difference between a bulla and vesicle?
Vesicle <1cm
Bulla >1cm
->most of these definitions mean small <1cm and large >1cm
List some of the most common skin conditions.
Acne
Psoriasis
Rosacea
Skin lesions
Urticaria
Warts
Leg ulcers
Scalp/nail disorders
Eczema
Infections
What is the treatment of an abscess?
Incision and drainage
What is meant by the distribution of dermatosis?
How the lesions are scattered are spread out
e.g. are they all close together or spread in different parts of the body
What is Acanthosis Nigricans?
Hyperkeratosis and hyperpigmentation and papules
Velvet-like appearance
Dark brown/grey
What is Acanthosis Nigricans associated with?
Insulin resistance
Obesity
Malignancy
List some conditions in which skin signs can point towards the condition.
Erythema Nodosum
Sarcoidosis
Vasculitis
Malignancy
Autoimmune conditions
If a patient has eruptive xanthoma, many papules (small raised), what might you suspect as an underlying cause?
Hyperlipidaemia
What are some investigations used in dermatology if bacterial infection is suspected?
Charcoal swab
Microscopy, culture and sensitives of the swab
What are some investigations used in dermatology if viral infection is suspected?
Viral swab for PCR
If systemic illness, take a throat swab
->can swab vesicle/bulla if vesicular eruption
What are some investigations used in dermatology if fungal infection is suspected?
Skin scraping
Nail clipping
Hair sample
Fungal cultures of each
What is a simple method used to take a skin biopsy?
Punch biopsy
Going back to skin structure, what is the role of the subcutaneous tissue?
Fat energy store
Insulation
Fibrous bands which anchor skin to fascia
What is the predominant cell type in the epidermis?
Keratinocytes
What are the three types of cell in the
dermis?
Keratinocytes
Melanosomes
Langerhans cells
What do Langerhan cells do?
Process antigens and migrate to lymph noses to induce an immune response
What do melanocytes make?
Melanosomes (collections of melanin)
