Introduction to Dermatology Flashcards
What skin condition can happen in diabetes?
Dermatolipsclerosis
What is pitiriasis?
Scaling
What pathological processes can occur in the skin?
Infective Immunological Neoplastic - Benign; eg: psoriasis - Malignant Inflammatory Traumatic Metabolic Genetic
Which part of the skin structure is psoriasis a disease of?
Basement membrane
Abnormal epidermal cells > produce keratin > scale
Which part of the skin does urticaria occur in?
Dermis
What are the functions of the skin?
Protection from environment - Physical - Immune Thermoregulation Vitamin D synthesis Keeps organs inside Sensation Aesthetic
What are the three layers of the skin, from superficial to deep?
Epidermis
Dermis
Subcutis/panniculus/hypodermis
What primarily makes up the epidermis?
Keratinocytes
What primarily makes up the dermis?
Fibroblasts
Collagen
Elastic fibres
What makes up the hypodermis?
Fat
What are the four main layers of the epidermis, from superficial to deep?
Stratum corneum
Stratum granulosum = granular cell layer
Stratum spinosum = spiny layer
Stratum basale = basal cell layer
In which direction do epidermal cells mature?
Deep to superficial
Describe the stratum basale
Source of epidermal stem cells
Site of cell division
Keratinocytes start here and move upwards
Describe the stratum spinosum
Centre of epidermis
Has spiny appearance due to desmosomal junctions
Describe the stratum granulosum
Lipids produced by keratinocytes secreted into extracellular space
Forms water barrier > keeps water in skin
Describe the stratum corneum
Made of desquamating keratinocytes
Thick outer layers of flattened keratinised non-nucleated cells
Barrier against trauma and infection
What is the most common form of skin cancer?
Basal cell carcinoma
What are the cells of origin of basal cell carcinoma?
Basal keratinocytes
What are the three main cell types in the epidermin?
Keratinocytes
Melanocytes
Langerhans cells
What is the ratio of keratinocytes to melanocytes?
10:1
What do melanocytes do?
Produce pigment = melanin
Transfer melanin to keratinocytes via dendrites in stratum basale
What are melanocytic nevi?
Moles = benign collections of melanocytes
What is a melanoma?
Malignancy of melanocytes
What is the main function of Langerhans cells?
Immune = dendritic cells
What are the two layers of the dermis?
Papillary dermis
Reticular dermis
What is the function of the dermis?
Support
What does the dermis contain?
Blood Lymphatics Nerves Sweat glands Hair follicles
What are the cells of the dermis?
Fibroblasts
Mast cells
What are kelloids?
Abnormal scars
Uncontrolled synthesis and excessive deposition of collagen at sites of prior dermal injury and wound repair
What is the major effector cell in urticaria?
Mast cell
What is the function of the hypodermis?
Insulates body
Energy supply
Cushions and protects skin
Allows for skin mobility over underlying structures
What is erythema nodosum?
Inflammation of hypodermis
What makes up the pilosebaceous unit?
Hair follicle Sebaceous glands Apocrine glands - Only in axillary and anogenital areas - Open directly into hair follicle Arrector pili muscle
Where do eccrine glands open to?
Directly onto skin surface
Present throughout body
What questions do you ask in a history of a rash?
When did it begin? - Context of onset Where on the body did it begin? How has it evolved so far? - Sites - Has the rash itself changed? Symptoms of rash Have you had something similar before Other sites involved - Mucosal surfaces - Hair - Nails - Teeth Exacerbating factors Have you tried any treatments? Have you come into contact with any new substances? Have you started any new medications? Associated features Have others around you had a similar rash?
What are the red flag symptoms associated with a rash?
Shortness of breath Tongue swelling Joint pain Fever and sweats New lumps or bumps
What questions do you ask in a history of a lesion?
When did it develop? Is it new or old? Does it come and go, or stay? How many lesions are there? How has it changed over time? - Size - Shape - Colour Have you had a similar lesion before? Symptoms of lesion Sun exposure history Past history of skin cancers Treatment for skin cancers in past Family history of skin cancers
What is erythema?
Redness of skin due to vasodilation
What is erythroderma?
Erythema over >90% of body surface area
What is scale?
Abnormal accumulation of keratin
Surface change
What is a macule?
Flat area of altered skin colour
Impalpable
What is a papule?
Elevated lesion
Less than 5 mm
What is a nodule?
Elevated lesion
More than 5 mm
What is a cyst?
Nodule with fluid within
What is a plaque?
Circumscribed, elevated area of skin
Breadth greater than thickness
What is a wheal?
Area of localised oedema of skin
What is a vesicle?
Fluid-filled blister
What is a pustule?
Vesicle/bulla containing pus
- Pus can be sterile
What is an erosion?
Superficial loss of epidermis
Doesn’t scar
What is an ulcer?
Area of tissue loss through dermis
Forms scar
What is a crust?
Scab = dried exudate
Forms erosion/ulcer
What is telangiectasia?
Dilated blood vessels
What are petechiae?
Pinpoint bleeding into skin/mucosae
Doesn’t blanch
What are purpura?
Discolouration of skin/mucous membranes
Due to bleeding from small vessels
Non-blanching
What is sclerosis?
Hardening of subcutaneous tissue and dermis
What is atrophy?
Thinning of epidermis
How do you describe the distribution of a skin pathology?
Flexural/extensor
Sun-exposed
Follicular/non-follicular
Symmetrical
What are red flags in skin pathology?
Skin pain Blisters/pustules, especially if widespread Punched out lesions Mucosal involvement Rapid change in any presentation Purpura Confluent erythema Facial swelling Tongue swelling Hoarse voice Difficulty swallowing/breathing Urticaria Change in - Size - Shape - Colour
What are other concerning features associated with skin lesions?
Shortness of rbeath Joint pain and swelling Fever Sweats Lymphadenopathy Pregnancy Contacts
