Hair loss/excess Flashcards
What are the 3 different types of hair in humans ?
- Lanugo : fine long hairs covering the foetus. Shed about 1 month before birth
- Vellus : fine, short hair covering much of body surface. Replaces lanugo hairs before birth
- Terminal : long, coarse hairs eg scalp & pubic area. Growth influenced by androgen levels
What are the 4 phases of hair growth ?
- Anagen: actively growing hair, can last upto 6 years, 85-90% in this phase
- Catagen: in-between phase of 2–3 weeks when growth stops and the follicle shrinks
- Telogen: resting phase for 1–4 months
- Exogen: release of dead hair
Loss of how much scalp hair per day is normal ?
50-150
List the causes of generalised hair loss
- Telogen effluvium (excessive shedding) – occurs 2-6months after an event eg severe illness, childbirth, stress
- Endocrine – eg thyroid disease
- Drugs - contraceptives, anticoagulants, anti-convulsants
- Dietary deficiency: iron / zinc / vitamin D
- Diffuse alopecia areata
- Malnutrition
- Androgenetic alopecia
What are the 2 categories of localised hair loss ?
Scarring & non-scarring
List the causes of localised non-scarring hair loss
- Alopecia areata
- Androgenetic
- Trichotillomania
- Traction alopecia
- Tinea capitis
List the scarring causes of localised hair loss
- Burns / trauma
- CDLE
- Lichen planus
- Frontal fibrosing alopeci
What investigations may be done in someone presenting with hair loss ?
- Skin scrapings and hair pluckings
- Woods lamp examination
- Dermoscopy
- Scalp biopsy +/- DIF (direct immunofluorescence)
- Blood tests - FBC, TFTs, Iron / zinc levels, Hormone profile
What is alopecia areata?
- A chronic, inflammatory condition affecting the hair follicles which leads to sudden onset of non-scarring alopecia (hair loss).
- The result is localised one or more round bald patches appear suddenly, most often on the scalp.
What are the clinical features of alopecia areata ?
- Hair loss typically affects any hair-bearing area esp scalp or facial hair and is usually patchy and of sudden onset.
- Patches are round, well-circumscribed and smooth. Patches may coalesce into larger areas of alopecia. More rarely, hair loss may be diffuse.
- In the patches skin is normal-coloured or slightly red without scarring (the follicular openings are still present).
- Exclamation mark hairs (short broken hairs which taper proximally) may be seen at the edge or hair loss
- Nail changes include pitting, onycholysis, splitting, longitudinal ridging, red lanula, koilonychia, and leukonychia may occur.
When exammining the patches of hair loss in someone with alopecia areata what is seen ?
- Yellow / black dots
- Broken hair
- Tapering hair - “exclamation mark hair”
What is the treatment of aleopcia areata ?
Tx options include:
No treatment - hair will regrow in 50% by 1 year & 80-90% eventually
- If treatment wanted then 1st line = Try a potent or very potent TCS (do not use for facial areas)
- 2nd line = refer to dermatology, options include topical/systemic steroids, PUVA , DCP, Dithranol
Also should be informed on options of wigs & cosmetic camoflage
What is Trichotillomania?
- A disorder characterised by an irresistible urge to remove or pull one’s own hair, which results in alopecia (hair loss).
- It may develop as a coping mechanism triggered by stress or anxiety
Who does a disorder trichotillomania more commonly affect?
- People with OCD
- Commonly associated with other body-focused repetitive behaviours, such as nail biting (onychophagia), skin picking, acne excorié, lip biting and cheek chewing.
What are the clinical features of trichotillomania ?
- Most commonly affects the scalp
- Hair loss patterns vary from mild thinning or unnoticeable areas of hair loss to completely bald areas.
- It may occur when the individual is engaged in other activities such as watching television, reading etc. Or deliberately associated with compulsive urges and anxiety that are alleviated by hair pulling.
- Examination of the scalp may reveal irregularly-shaped patches of alopecia.
- They may feel stubbly, with hairs of varying lengths.
- Children tend to pull on hairs that are easy to reach and are on the same side as their dominant hand. These are usually the frontotemporal areas (areas behind the forehead and ears) and the vertex (top of the head).