Describe general hair anatomy? Use terms such as infundibulum and isthmus, hair bulb
infundibulum - from hair shaft = follicular orifice (visible hair) to sebaceous duct entrance
isthmus - from sebaceous entranced to hair bulge (attachment of arrector pili muscle = smooth muscle)
below that: hair stem and hair bulb
What does hair bulb contain?
- dermal papilla - specialized fibroblasts that can induct with epidermis
- matrix (around papilla):
- melanocytes (hair colour)
- blood vessels around
- melanocytes (hair colour)
- blood vessels around
Why is hair bulge so important? Where is it located?
Hair bulge is location where arector pili is connecting to hair
Location of follicular stem cells
What is a hair shaft? What layers is it made of?
Hair shaft = visible hair (above epidermis)
contains medulla (inside, spongy keratinocytes, no nuclei),
cortex - main bulk of hair - malanin/macrofibrils,
and cuticle: 6-8 layers around hair, overlapping like roof tiles
What is inner root sheath? What is an outer root sheath?
Inner root sheath - rigid cylindrical tube around hair, develops before hair to bold it into shape, disintegrates at the level of sebaceous gland
Outer root sheath - function unknowm, from hair bulb to epidermis, continous with epidermis
red line on image - inner root sheath (structure)
purple line - outer root sheath (function unknown)
What are the 3 phases of hair growth?
- anagen - active growth - years (1000 days on scalp, 28 on eyebrows)
- catagen - involution (shrinking) - 1-2 weeks
- telogen - rest (100 days)
- return to anagen
briefly discuss androgenetic alopecia?
- 50% of women and men by age 50 (50/50)
- reduction of testosterone to DHT (dihydrotestosterone) in balding areas (andro - part)
- strong genetic component (genetic part), can be inherited from maternal or paternal side
- treat with oral finasteride ( 5α-reductase inhibitor, 5α- is an enzyme that converts testosterone to dihydrotestosterone (DHT), also used in benign prostetic hyperplasia); minoxidil (minoxidil is an antihypertensive vasodilatormedication, which slows or stops hair loss and promotes regrowth), or hair transplant surgery
briefly discuss alopecia areata?
- non-scarring, pathology not understood
- circumscribed circular patch (es), may have some broken hairs on periphery
- exclamation point hairs - hairs that are narrower closer to the scalp and therefore mimic an exclamation point - pathognomonic
- may affect eyebrows, eyelashes, beard
- unpredictable course, 50% self-resolve within a year without treatment
- 25% have family Hx
- 40% of patients have nail changes, such as pitting
briefly discuss trichotillomania?
tricho - hair ; tillo - pull
repetitive pulling and plucking of one's hair
results in unnatural paterns
only 5% of trichotillomania have deep psychological disorders
some also swallow hair (trichophagy), which can be life-threatening because can cause partial intestinal obstruction
briefly discuss tinea capitis?
- caused by organisms
- in BC, most common is Microsporum canis (found in cats and dogs - ask about pets), M. canis not contagious from human to human
- other organism is Trichophyton tonsurans (tricho - hair), contagious from human to human
- can be non-inflammatory or inflammatory (for ex. if secondarily infected by Staph)
- can have scarring
- diagnose by KOH scraping (will dissolve keratinocytes, so organisms will be seen; mycologic culture, Wood's lamp - hairs infected by microsporon fluoresce due to a substance organism produces
briefly discuss telogen effluvium?
- excessive shedding of normal hairs
- can be triggered by drugs, stress, diets, crash diets, etc
- termination of anagen phase -> catagen -> telogen
- to notice difference, must get reduction from 100,000 to 50,000 hairs
- normal regrowth in 6 months
discuss anagen effluvium?
- decrease or complete stop of proliferation of matrix cells of the hair shaft (inside)
- occurs a few days to weeks after insult (similar to telogen effluvium) - ex. chemo or radiation
discuss scarring alopecia ?
- less common than nonscarring - potential for irreversible permanent hair loss
- ex. discoid lupus erythematosus
- ex. lichen planopilaris
What are some hair loss Hx questions?
Hair loss history questionnaire
- What is the duration and pattern of the hair loss?
- Is the hair coming out by the roots, or is it breaking?
- Increased shedding or increasing thinning?
- Age of onset
- Menses, pregnancy, menopause
- Present and past health
- Thyroid function screening questions
- Family history
- Hair care, hair cosmetics
What can be on your differential for hair loss?
Hair coming out by roots
- Telogen effluvium
- Androgenetic alopecia
- Alopecia areata
- Drugs (anagen or telogen effluvium)
- Tinea capitis
- Structural hair shaft abnormalities
- Breakage due to improper use of haircare cosmetics
- Anagen arrest
How can hair pull test be used for diagnosis?
- A hair pull test is very helpful to determine if hair loss is active. Approximately 60 hairs are grasped between the thumb, index and middle fingers from the base of the hairs near the scalp and firmly tugged away from the scalp. If > 6 are pulled, then this is a positive pull test.
- Scalp biopsy may be necessary to make diagnosis.
Outline basic elements of nail?
covers fingertip like a watch glass
corneocytes are flattened, anuclear and devoid of organelles
angle between the nail plate and the dorsum of the digit skin is Lovibond's angle
melanocytes may be present, contributing to pigmentation of the nail plate
nail growth is continuous throughout life: 0.5-1.2 mm/week
toenails grow at 33%-50% the rate of fingernails
regeneration of a fingernail after forceful removal is 160 days
What is onychomycosis?
Fungal infection is an extremely common cause of toenail dystrophy
Great toenail is extremely prone to infection
Infection of fingernails may occur in nails previously traumatized or when nail involvement is part of tinea mannum
Onycholysis: separation of nail plate from nail bed
Subungual hyperkeratosis: buildup of soft yellow keratin in the space created by the onycholysis, usually asymptomatic
Most due to Trichophyton rubrum, but in a few cases, Epidermyophyton floccosum and Trichophyton mentagrophytes may be recovered. Diagnosis can be made by culture. Treatment is terbenafine or itraconazole orally
What nail changes are present in psoriasis?
Onycholysis, subungual hyperkeratosis, nail pitting, yellowish discoloration.
More serious nail dystrophies are often accompanied by inflammatory, arthritic changes in the distal interphalangeal joint
Extremely difficult to treat
on picture: psoriasis showing marked subungual debris.
What are Beau's groves?
- 1 mm wide depression in the nail plate that extends horizontally from one lateral nail groove to the other
- all nails are simultaneously affected
- most commonly develop following dramatic illness such as MI and periods of high fever or malnutrition
- will tell you if patient was hospitalized and when - takes 6 months to grow out nails
What is clubbing?
Lovibond’s angle greater than 180 degrees, most commonly seen with chronic pulmonary or cardiopulmonary disease but also occurs with some tumors, especially those of the lung parenchyma
What are periungual warts?
Often distort the nail plate
In most instances, the dystrophy is not permanent and the nail plate returns to normal following therapeutic or spontaneous resolution of the warts
What is one cause of white banding on nails?
Horizontal white banding or opacification occurs in hypoalbuminemia accompanying chronic hepatic or renal disease
What are some causes of brown banding on nails?
Vertical - secondary to nevus or melanoma
Horizontal - Addison's disease, cancer chemotherapy
What are some causes of splinter haemorrhages?
Thin dark red lines 1-3 mm in length, representing small hemorrhages at the junction of the nail plate and the nail bed. They move out as the nail grows.
Seen with bacterial endocarditis, trichinosis, but frequently seen in normal individuals as cause of trauma
How does bacterial paronychia look like?
Usually caused by Staphylococcus
Redness, warmth, swelling and tenderness
if Pseudomonas, bluish black
What is koilonychia?
Spoon-shaped nails may be due to iron deficiency
can also be in alopecia errata
What are some differentials for white and ulcerating lesions in the mouth?
White lesions of the mouth:
Squamous cell carcinoma
Oral hairy leukoplakia
Ulcerating lesions of the mouth:
Stevens Johnson syndrome/erythema multiforme major
Hyperpigmentation of the Oral Mucosa:
Foreign materials: amalgam tattoos, carbon, seeds, leaves of various plants, tobacco
Pharmacologic agents: minocycline, AZT, antimalarials, amiodarone, OCP, doxorubicin
Heavy metal exposure: bismuth, mercury, silver, lead, tin, copper
Systemic disease: Addison’s disease, Peutz-Jeghers syndrome, hemochromatosis
Neoplasms: nevi, oral and labial melanotic macules, melanoma
Reactive process: postinflammatory hyperpigmentation