Introduction to General Dermatology Flashcards
Which cells are found in higher numbers in darker skin?
Melanozomes rather than melanocytes
Which layer of the skin provides its strength?
The dermis
What is the most populous cell type in the dermis gel?
Fibroblasts
In which layer of the skin are the majority of its components found?
The dermis
What are the three main layers of the skin?
Epidermis
Dermis
Hypodermia (subcutaneous tissue)
Describe the basal cells becoming superficial dead skin cells
The basal cells of the stratum basale divide by mitosis and begin to migrate upwards getting more superficial. As they do this they lose their nuclei and begin to flatten. After around one month, they are dead and flattened cells that have reached the surface and from the stratum corneum, the most superficial part of the skin
Give some functions of the skin
Thermoregulation
Skin immune system - inane and adaptive functions
Barrier - against mechanical, chemical, microorganisms, UV light. Keeps in water, electrolytes, macromolecules
Sensation - temperature, touch, pain
Vitamin D synthesis
Interpersonal communication - physical appearance, smell, self-identity
What proportion of the population are affected by skin disease?
Around 25%
Give some external causes of skin disease
Temperature UV Chemical - allergen or irritant Infection Trauma
Give some internal causes of skin disease
Systemic disease
Genetics
Drugs
Infection
How does photosensitivity present?
With obvious neck and arm ‘tan lines’ which can come on after very brief UV light exposure
What is the most common cause of photosensitivity?
Drug induced
Why must patients with photosensitivity be tested for various wavelengths of light?
They may be sensitive to any of, including a combination of, UVA, UVB and visible light
What is cold urticaria?
An abnormal response to cold stimuli
There is a mast cell hypersensitivity in the skin which causes an abnormal nettle sting-like reaction to non-extreme cold stimulation
What is dermatitis artefacta?
Traumatic skin injury/disease inflicted by the patient. Usually the patient reports no memory of how the damage occurred and these cases are commonly linked with psychiatric illness
What is the most common internal cause of skin disease and the most common in-hospital referral type for dermatologists?
Drug reactions
What is the pathophysiology of bullies pemphigoid?
Autoimmune condition where the body attacks the proteins which anchor the epidermis and so it is severed from the layer below and bull appear pushing through the surface
What is the difference between pemphigoid and pemphigus?
Pemphigoid is deep bullae whereas pemphigus is more superficial and blister-like
PemphigoiD = DEEP PemphiguS = SUPERFICIAL
What are macules and patches?
A macule is a small 1cm circumscribed area
They cannot be felt by touch but are identifiable and clearly bounded by their colour change
What are papules and plaques?
A papule is a small 1cm raised area
What are vesicles and bullae?
A vesicle is a small 1cm fluid filled lump
What are pustules and abscesses?
A pustule is a small 1cm pus filled lump
What are erosions and ulcers?
An erosion is a loss of only the epidermis - it will not scar
An ulcer is a loss of at least the epidermis and dermis (but may progress to an unlimited level) - it will scar
What area of disease is pyoderma gangrenosum
Bowel disease
