Session 6 Flashcards
Learning outcomes
- Ability to describe the functions of the skin
- Ability to describe the structure of normal skin
• Ability to describe the functions of the skin LO
Functions of the skin?
- Protective barrier against environmental insults
- Temperature regulation
- Sensation
- Vitamin D synthesis
- Immunosurveillance
- Cosmesis
What is Erythroderma?
Intense and usually widespread reddening of the skin due to inflammatory skin disease. It often precedes or is associated with exfoliation (skin peeling off in scales or layers), when it may also be known as exfoliative dermatitis (ED).
Erythroderma complications (6)
- ‘Total skin failure’
- Hypothermia (loss of thermoregulation)
- Infection (loss of protective barrier)
- Renal failure (insensible losses)
- High output cardiac failure (dilated skin vessels)
- Protein malnutrition (high turnover of skin)
Erythroderma
- >90% of body surface area affected, erythematous (?) and exfoliatitive
- Causes:
- Symptoms:
- Signs:
- Reddening of the skin,
- psoriasis, eczema, drugs, cutaneous T cell lymphoma
- pruritus, fatigue, anorexia, feeling cold
- erythematous, thickened, inflamed, scaly, no sparing
Epidermis
4 major cell types each with individual function
- Keratinocytes - protective barrier
- Langerhan cells- antigen presenting cells
- Melanocytes- produce melanin which provides pigment to the skin and protects cell nuclei from UV DNA damage
- Merkel Cells - contain specialised nerve endings for sensation
Epidermis
- 4 layers of the epidermis
- Each layer represents a different stage of maturation of the keratinocyte
- Average epidermal turnover time is about ?
- The 4 layers of the epidermis include: ?
30 days
stratum corneum (horny layer- most superficial)
stratum granulosum,
stratum spinosum (prickle layer),
stratum basale (basal layer),
• Stratum lucidum found in areas of thicker skin such as palms and soles
Epidermis
Pathology of the epidermis may cause:
a) Change in epidermal turnover
b) Change in surface of the skin
c) Changes in pigmentation of the skin
What are these two images showing
-
Dermis
- Composed of ?
- Provides ?
- Also contains ?
- collagen, elastin and glycosaminoglycans
- Strength and elasticity
- immune cells, nerve cells, skin appendages, lymphatics and blood vessels
What are these images showing
-
- Produce sebum through?
- Secrete sebum on to skin which?
- Active after puberty
- Stimulated by conversion of ?
- Increased sebum production and bacterial colonisation in conditions such as ?
- hair follicles (pilosebaceous unit)
- Lubricates skin
3.
- Androgen to dihydrotestosterone
- acne vulagris
Eccrine and Apocrine glands
- Function
- Innervated by ?
- Two types: ?
- Regulate body temperature
- sympathetic system
- Eccrine - widespread
Apocrine - active following puberty and are found in axillae, areolae, genitalia and
anus.
Eccrine glands
- Function
- Location
- Innervation
- Sweat - thermoregulation
- highest density in palms and soles, then on the head, but much less on the trunk and the extremities
- Cholinergic sympathetic nerve
An apocrine sweat gland
- Structure
- Location
- Modified apocrine glands include ?
- Innervation
- Coiled secretory portion located at the junction of the dermis and subcutaneous fat, from which a straight portion inserts and secretes into the infundibular portion of the hair follicle.
- The axillae(armpits), areola and nipples of the breast, ear canal, eyelids, wings of the nostril, perianal region, and some parts of the external genitalia.
- the ciliary glands in the eyelids; the ceruminous glands, which produce ear wax; and the mammary glands, which produce milk.
- Adrenergic nerves
Hair
- Each hair consists of modified keratin and is divided into ?
- 3 main types of hair:
- Each hair follicle enters a growth cycle which has 3 main phases:
- hair shaft and hair bulb
- lanugo hair, vellum hair (short hair all over body), terminal hair (coarse long hair)
- anagen, catagen, telogen
What is this image showing?
-
Nails
- Consists of a nail plate which arises from the ? at the posterior nail fold and rests on the nail bed.
- Nail bed contains ?
- nail matrix
- blood capillaries
What are these images showing?
-
LEARNING OBJECTIVES
- Take a dermatological history
- Examine skin, hair, nails, and mucous membranes systematically
- Describe cutaneous physical signs
- Apply these skills to a patient presenting with a skin problem - role-play cases
• Take a dermatological history LO
How do you take a dermatological history
What questions should you ask
- Presenting complaint -> • Nature (e.g. rash vs lesion) • Site • Duration
- History of presenting complaint -> • Initial appearance and evolution* • Symptoms (particularly itch and pain) • Aggravating and relieving factors (“triggers”) • Previous and current treatments (effective or not) * Indicates points more important with lesions as presenting complaint
- Past medical history -> • Systemic diseases • History of atopy (asthma, hay fever, eczema) • History of skin cancer or pre-cancer* • History of sunburn/sunbathing/sun-bed use* • Skin type*
- Family history -> • Family history of skin disease* • Family history of atopy • Family history of autoimmune disease
- Social history -> • Occupation (• Sun exposure* • Contactants) • Improvement in PC when away from work
- Drug history and allergies -> • Regular and recent • Systemic and topical • Get specific with topical treatments (• Where? • How much? • How long for?)
- Impact on quality of life / ICE -> • Impact of skin complaint on life • Ideas • Concerns • Expectations
• Examine skin, hair, nails, and mucous membranes systematically LO
What four things are you examining for?
Inspect
Palpate
Describe
Systematic check (Whole skin Hair, nails, mucous membranes)
What does describe entail?
- S - Site, distribution (rash) • or Size and Shape (lesion)
- C - Colour (and Configuration)
- A - Associated changes e.g. surface features
- M - Morphology
What do we use for pigmented lesions?
ABCD FOR PIGMENTED LESIONS
- Asymmetry
- Border (irregular or blurred)
- Colour
- Diameter
What are the four ways to describe site & distrubution?
What are the four ways to describe configuration
hypersensitivity reaction usually triggered by infections, most commonly herpes simplex virus (HSV). It presents with a skin eruption characterised by a typical target lesion.
Erythema multiformae
What are the four ways to describe colour?
What are the four ways to describe surface features
What are the four ways to describe the morphology
What four ways could you describe (more serious - well to me) morphologies?
Describe cutaneous physical signs LO
What four morphologies have we missed?
Label these hair findings
Label these nail findings
What is the diagnosis?
ATOPIC ECZEMA (DERMATITIS) Diagnosis?
Distinguish from psoriasis
Well defined plaque Excoriation Flexural Scaly Crusting Ill defined PMH of asthma, allergies etc
MANAGEMENT OF ATOPIC ECZEMA
- Avoid irritants e.g. soap, fragrance, HDM, wool, animal fur
- Emollients (moisturisers) to restore skin barrier
- Topical corticosteroids daily until inflammation clear
- Mild or moderate for face
- Moderate or potent for body/limbs
- Antihistamines for pruritus (sedating overnight)
What is this image showing? I.e. diagnosis
Asymmetrical Irregular borders
SUSPECTED MELANOMA
• Refer on urgent cancer pathway if:
• >3 points
• Suspected nodular MM
• Dermoscopy suggests melanoma
- Mechanism of erythema
- Causes of erythema
- caused by hyperemia (increased blood flow) in superficial capillaries
- Infection, massage, electrical treatment, acne medication, allergies, exercise, solar radiation (sunburn), cutaneous radiation syndrome, mercury toxicity, blister agents, niacin administration, or waxing and tweezing of the hairs—any of which can cause the capillaries to dilate, resulting in redness. Erythema is a common side effect of radiotherapy treatment due to patient exposure to ionizing radiation.
Purpura
- Mechanism
- Causes
- They measure 0.3–1 cm (3–10 mm), whereas ? measure less than 3 mm, & ? greater than 1 cm
- bleeding underneath the skin
- vasculitis
- dietary deficiency of vitamin C (scurvy)
- common in typhus
- Neisseria meningitidus -> Gram-negative diplococcus organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation (DIC). The DIC is what appears as a rash on the affected individual.
- vasculitis
- petechiae, ecchymoses
Hyperpigmentation is associated with a number of diseases or conditions, including the following:
Addison’s disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis, such as melanocyte-stimulating hormone (MSH), are frequently elevated.
Cushing’s disease or other excessive adrenocorticotropic hormone (ACTH) production, because MSH production is a byproduct of ACTH synthesis from proopiomelanocortin (POMC).
- Pathogenesis of hypopigmentation
- Melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin
Hypopigmentation is seen in:
Albinism
Idiopathic guttate hypomelanosis
Leprosy
Lleucism
Phenylketonuria
Pityriasis alba
Vitiligo
Angelman syndrome
Tinea versicolor
An uncommon adverse effect of imatinib therapy
What is keratin?
- Fibrous structural protein
- insoluble in water and organic solvents
- large amounts of the sulfur-containing amino acid cysteine, required for the disulfide bridges
Hirsuitism
- What is it?
- Causes
- excessive body hair in men and women on parts of the body where hair is normally absent or minimal, such as on the chin or chest in particular,
2.
The following are conditions and situations that have been associated with hyperandrogenism and hence hirsutism in women:
Hyperinsulinemia (insulin excess) or hypoinsulinemia (insulin deficiency or resistance as in diabetes).
Ovarian cysts such as in polycystic ovary syndrome (PCOS), the most common cause in women.[8]
Ovarian tumors such as granulosa tumors, thecomas, Sertoli–Leydig cell tumors (androblastomas), and gynandroblastomas, as well as ovarian cancer.
Hyperthecosis.
Pregnancy.
Adrenal gland tumors, adrenocortical adenomas, and adrenocortical carcinoma, as well as adrenal hyperplasia due to pituitary adenomas (as in Cushing’s syndrome).[9]
hCG-secreting tumors
Inborn errors of steroid metabolism such as in congenital adrenal hyperplasia, most commonly caused by 21-hydroxylase deficiency.[9]
Acromegaly and gigantism (growth hormone and IGF-1 excess), usually due to pituitary tumors.[9]
Use of certain medications such as androgens/anabolic steroids, phenytoin, and minoxidil.
Causes for koilonychia (spooning)
- iron defiency anaemia
- Plummer–Vinson syndrome (difficulty in swallowing, iron-deficiency anemia, glossitis, cheilosis and esophageal webs)
Causes of pitting
Patients with psoriasis
What is Leukonychia totalis?
- whitening of the entire nail
- hypoalbuminaemia (low albumin), which can be seen in nephrotic syndrome (a form of kidney failure), liver failure, protein malabsorption and protein-losing enteropathies. A genetic condition, and a side effect of sulphonamides (a family of antibiotics) can also cause this appearance.
