follow @PCDSUKCreated: 23rd November 2012 | Last Updated: 24th April 2017
Introduction
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This chapter provides an overview of alopecia (excluding the genetic hair shaft defects) and is set out as follows: |
Aetiology
The hair cycle
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Hair follicles undergo a repetitive sequence of growth and rest known as the hair cycle. To understand the different causes of hair loss it is important to have a comprehension of the hair cycle
- Anagen - is the period of active growth and may last for several years. Under normal circumstances 80-90% of hair follicles on the human scalp are in anagen at any one time
- Catagen - at the end of anagen, epithelial cell division declines and ceases, the hair follicle enters an involutionary phase known as catagen
- Telogen - the period between the completion of follicular regression and the onset of the next anagen phase is known as telogen, during which time the hair is shed
- Kenogen - in the human scalp, hair follicles may remain in a state of latency, also known as kenogen, for a prolonged period after the hair is shed
- The term telogen effluvium is broadly used to describe any cause of diffuse hair shedding in the telogen phase, and results from the premature termination of anagen with a subsequent reduction in the length of the hair cycle
Clinical findings
Non-scarring or scarring alopecia?
The first step to making a diagnosis is to differentiate whether the alopecia is non-scarring or scarring
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Non-scarring alopecia
- No clinically visible inflammation is noted in most cases
- Atrophy absent
- Tufting absent
- Tends to have preserved follicular openings
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Scarring alopecia (figure 19)
- Clinical inflammation is frequently, but not always, present
- Atrophy
- Tufting of hairs
- Loss of follicular openings
Non-scarring alopecia - male and female pattern
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Male pattern alopecia (figures 1 & 2)
- Recession of the frontal hair line, mainly in a triangular pattern is the characteristic finding, later followed by thinning of the vertex
- Refer to the related chapter Alopecia - male and female pattern alopecia for more information
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Female pattern alopecia (figure 3)
- The Ludwig pattern - is characterised by a diffuse thinning of the centroparietal region with maintaining of the frontal hair line. It is the most common type in women, occasionally also observed in men
- The Christmas tree pattern - this is similar to the Ludwig pattern in that the Christmas tree pattern shows diffuse centro-parietal thinning, but additionally, the frontal hair line is breached
- Refer to the related chapter Alopecia - male and female pattern alopecia for more information
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If associated with hirsutism or other signs of virilisation also refer to the related chapter Hyperandrogenism
Non-scarring alopecia - diffuse
Acute:
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Drugs
- In particular chemotherapy agents, which cause hairs to fall out in their anagen growth phase, referred to as anagen effluvium (figure 4)
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Acute telogen effluvium
- Normally occurs two to three months after a triggering event such as pyrexia (in particular a body temperature of 102.5 degrees Fahrenheit and above), child-bearing, major surgery, weight loss and certain medications
- In one-third of cases no trigger is identified
- Unless the trigger is repeated, spontaneous complete regrowth occurs within three to six months
More gradual:
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Other causes of telogen effluvium
- Thyroid disorders (figures 5 & 6)
- Profound iron deficiency anaemia (figure 7) can cause a diffuse hair loss. The association between iron deficiency and no or mild anaemia and chronic diffuse hair loss is controversial, however, a trial of iron supplements is worthwhile for ferritin levels < 40
- Increasing age
- Many drugs have been implicated with hair loss in the telogen phase although good evidence for a link is not often evident. A dose-related diffuse alopecia is commonly seen with acitretin
- Crash dieting
- Various - disorders causing malabsorption, hepatic and renal disorders, malignancy, SLE and dermatomyositis can all cause telogen hair loss
- Zinc deficiency, both acquired (from long-standing parenteral nutrition) and inherited, can be associated with a severe telogen effluvium. Acrodermatitis enteropathica is a rare genetic disorder associated with the malabsorption of zinc and characterised by diarrhoea, an inflammatory rash around the mouth and / or anus, and alopecia
- Alopecia areata - occasionally the initial hair loss may be diffuse
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Secondary syphilis (figures 8 & 9)
- Is non-inflammatory and can present with a diffuse pattern of alopecia, a moth-eaten pattern or a combination of both. The scalp is the most commonly affected area. However, the eyebrows, eyelashes, axilla, pubis, chest, and legs can also be affected. Alopecia syphilitica often accompanies other mucocutaneous symptoms of secondary syphilis, but it can be the only presenting symptom
- Investigations - all patients with diffuse alopecia require a FBC, ferritin and TFT. The need for any additional tests depends on the history / examination as above
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Chronic telogen effluvium (CTE)
- CTE is a primary idiopathic and often self-limiting condition affecting middle-aged women
- Women, especially with longer hair, describe large amounts of hair shedding and the patient may bring the hair to the consultation
- On examination the patient has a good head of hair appropriate to their age with no widening of the central parting line
- Despite of the shortened hair cycle, which may go on for several years, women with CTE should be reassured that the natural history is NOT that of a progressive alopecia (unless the patient also has female pattern alopecia, the two conditions can co-exist)
- Occasionally such patients may have a dysmorphophobia, a psychiatric condition, the hallmark of which is a fixation on an imaginary flaw in the patient's physical appearance, or in cases in which a minor defect truly exists the patient exhibits an inordinate amount of anguish
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Provide the patient with a patient information leaflet
Non-scarring alopecia - more patchy
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Alopecia areata (figure 10)
- The characteristic initial lesion is a circumscribed, totally bald, smooth patch. The skin within the bald patch is normal or slightly reddened. Short broken hairs (exclamation mark hairs) are often seen around the margins of active expanding patches of alopecia, and yellow dots can be seen around hair follicles
- Refer to the related chapter Alopecia areata for more information
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Tinea capitis (figure 11)
- Can cause non-scarring or scarring alopecia
- Hair loss tends to be patchy, but is often associated with subtle inflammation / scale
- Refer to the related chapter Tinea capitis for more information
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Trichotillosis (formerly called trichotillomania) - hair pulling (figures 12-16)
- Trichotillosis is a behavioural disorder characterised by compulsive hair pulling associated with an increase in tension prior to the pulling and a sense of relief when the hair is pulled out
- It is more common in women and can occur in people from all walks of life
- The hair manipulations frequently occur in patients engaged in sedentary activities
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Distribution
- The patches may be single or multiple
- The frontal and temporal scalp are most commonly affected, but any site can be involved
- The degree of involvement may vary from only a few square centimeters to large areas of scalp
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Unlike in alopecia areata
- The patches of alopecia may taken on unusual shapes
- It is uncommon for the hair to be completely lost within a patch of alopecia, and the remaining hair is firmly anchored in the scalp
- Hair length is not uniform - examination of the lesions with a magnifying glass / dermatoscope reveals various combinations of (1) newly growing short hairs with tapered ends, (2) broken short terminal hairs, (3) vellus or indeterminate hairs, (4) comedo-like black dots, or (5) empty follicular orifices
- The establishment of a good relationship between the physician and patient or parents of the affected child is important, as is the making of a confident diagnosis
- Management is mainly psychological support. Attempts should also be made to try and identify triggers for the patient's behaviour
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Traction alopecia (figures 17 & 18)
- Is due to certain hair styles which cause a sustained pull on the hair
- The pattern of hair loss is often distinctive and reflects the direction of traction
- Traction alopecia is most commonly seen in Afro-Caribbean hair styles when the hair is tightly braided. The hair loss commonly begins in the temporal regions and in front of / above the ears
- The presence of retained hairs along the frontal and / or temporal rim, termed the “fringe sign,” is a common finding in both early and late traction alopecia, and is a useful clinical marker of the condition
- Can be associated with headaches
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Changes are reversible if the style is changed early
Scarring alopecia
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Infection
- Bacterial infection eg a severe staphylococcal infection
- Tinea - refer to the related chapter Tinea capitis for more information (figures 20 & 21)
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Cicatricial alopecia
- Is the generic term used to describe circular / oval shaped patches of scarring alopecia
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The following conditions are all associated with cicatricial alopecia:
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Lichen planus (figure 22)
- Follicular erythema and keratotic plugs, which are commonly located at the periphery of expanding areas of alopecia
- Refer to the related chapter Lichen planus - follicular lichen planus for more information
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Discoid lupus erythematosus - DLE (figure 23)
- Much more common in women
- Scarring alopecia occurs in 20% of men and 50% of women with DLE
- Although DLE often presents on the face, the scalp can be the only affected site
- The scalp is often itchy
- Affected patches are erythematous and scaly with follicular plugging
- Patients are treated with UV-protection, super-potent topical steroids, intralesional steroids and antimalarial therapy
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Folliculitis decalvans (figure 24)
- Patients usually present with one or more round patches of scarring alopecia usually surrounded by pustules, crusting and sometimes erosions
- Refer to the related chapter Folliculits decalvans for more information
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Pseudopelade of Brocq (figure 25)
- Asymptomatic, slowly progressive, patchy cicatricial alopecia with no evidence of inflammation
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Two aetiological theories exist
- It is primarily an atrophic condition
- It is the end point of inflammatory conditions such as follicular lichen planus
- There is no known effective treatment
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Frontal fibrosing alopecia (figure 26)
- Presents as a progressive symmetric band-like alopecia, affecting the frontal hair line, the pre-auricular scalp and, less commonly and distinctively, the retro-auricular areas. ''Orphaned'' hairs ie isolated hairs, may remain in areas of hair loss
- Refer to the related chapter Lichen planus - follicular lichen planus for more information
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Acne keloidalis nuchae
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Acne keloidalis nuchae (AKN) is a condition characterised by follicular-based papules and pustules that form hypertrophic or keloid-like scars. AKN typically occurs on the occipital scalp and posterior neck and develops almost exclusively in young, African-American men. Refer to the related chapter for more information
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Acne keloidalis nuchae (AKN) is a condition characterised by follicular-based papules and pustules that form hypertrophic or keloid-like scars. AKN typically occurs on the occipital scalp and posterior neck and develops almost exclusively in young, African-American men. Refer to the related chapter for more information
Other, rare causes of scarring alopecia
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Dissecting cellulitis (figure 27)
- More common in black patients and between the ages of 18-40
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Presents with painful nodules and abscesses that taken on a cerebriform appearance. Can become extensive across the scalp
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Treatment - often requires a prolonged course of isotretinoin combined with short-term antibiotics and systemic steroids. Early intervention can prevent scarring. Click here for a patient information leaflet
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Pemphigus (figure 28)
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Pemphigus vulgaris affects middle-aged patients causing mucosal lesions, flaccid blisters on the skin and erosive scalp changes
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Pemphigus foliaceus is less severe than pemphigus vulgaris and mucosal lesions are uncommon
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Cicatricial pemphigoid
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Mainly affects elderly patients. This bullous disorder involves the eyes and / or other mucosal surfaces causing painful erosions and scarring. Patients with cutaneous involvement present with tense blisters and erosions, often on the head and the neck, with scalp involvement in 10% of cases
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Erosive pustular dermatosis of the scalp (figure 29-31)
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Affects the elderly with varying degrees of scarring associated with yellow-brown crusts, pustules, lakes of pus, erosions and ulceration. Previous UV damage, cryotherapy or other physical insults to the skin appear to play a role. Treatment is with super-potent topical steroids and UV protection
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Linear morphoea 'en coup de sabre' (figure 32)
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An atrophic band-like area of alopecia on the frontoparietal scalp and forehead
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Follicular mucinosis (figures 33 & 34)
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Benign follicular mucinosis - sometimes referred to as alopecia mucinosa - a benign condition. Early signs of the disease are the presence of grouped follicular papules arising in patches / plaques, usually 2-5 cm in diameter. Hair loss is common from the affected follicles. In some patients the condition resolves spontaneously and the hair regrows. In more severe disease complete follicular destruction prevents normal hair growth. Other features can include acneiform lesions
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Folliculotropic mycosis fungoides - this is due to a cutaneous t-cell lymphoma, and is characterised by a more generalised chronic form in a slightly older age group, with larger and more numerous plaques on the scalp, face and also the extremities
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Images
Please click on images to enlarge, or choose to download. Images must only be used for teaching purposes and are not for commercial use. Notice and credit must be given to the PCDS and any other named contributor.
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Figure: 1
Male pattern alopecia |
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Figure: 2 Same patient as figure 1 |
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Figure: 3 Female pattern alopecia Copied with kind permission from Dermatoweb
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Figure: 4 Anagen effluvium caused by tamoxifen |
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Figure: 5 Telogen effluvium secondary to thyrotoxicosis |
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Figure: 6 Same patient as figure 5 |
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Figure: 7 Iron deficiency anaemia This young lady had started to loose hair and thin out all over her scalp. Investigations revealed a low haemoglobin with a ferritin level of 3 |
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Figure: 8 Syphilis |
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Figure: 9 Syphilis |
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Figure: 10 Alopecia areata |
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Figure: 11 Tinea capitis |
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Figure: 12 Trichotillosis Different hair lengths |
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Figure: 13 Trichotillosis |
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Figure: 14 Trichotillosis An unusually shaped patch of hair loss |
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Figure: 15 Trichotillosis
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Figure: 16 Dermoscopic appearance of trichotillosis Hairs of different lengths and comedo-like black dots |
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Figure: 17 Traction alopecia Retained hairs along the frontal and temporal rim |
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Figure: 18 Traction alopecia Retained hairs along the frontal and temporal rim |
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Figure: 19 Scarring alopecia Atrophy and loss of hair follicles |
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Figure: 20 Tinea capitis and scarring |
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Figure: 21 A kerion |
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Figure: 22 Lichen planopilaris |
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Figure: 23 Discoid lupus erythematosus |
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Figure: 24
Folliculitis decalvans Copied with kind permission from Dermatoweb |
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Figure: 25 Pseudopelade of Brocq |
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Figure: 26 Frontal fibrosing alopecia |
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Figure: 27 Dissecting cellulitis |
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Figure: 28 Pemphigus vulgaris |
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Figure: 29
Erosive pustular dermatosis of the scalp |
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Figure: 30 Erosive pustular dermatosis of the scalp This patient had received numerous treatments for his actinic keratoses prior to this developing |
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Figure: 31 Same patient as above - post-treatment with potent topical steroids |
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Figure: 32 Linear morphoea 'en coup de sabre' |
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Figure: 33 Follicular mucinosis |
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Figure: 34 Follicular mucinosis |
Investigations
Investigations depend on the clinical context but can include:
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Swabs of pustules for C & S - the contents of the pustule should be expressed
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If tinea is suspected, scrapings of scale and plucked hairs should be sent for mycology
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Blood tests
- Female patients presenting with alopecia and hirsutism / irregular periods or other signs of virilisation need further investigations - refer to the related chapter Hyperandrogenism
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Diffuse alopecia - all patients with diffuse alopecia require a FBC, ferritin and TFT. The need for any additional tests depends on the history / examination eg ANA / ENA for suspected lupus, VDRL for suspected syphilis
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Biopsies
- The role of biopsies in scarring alopecia is controversial as the results will not necessarily provide much in the way of additional diagnostic information
- If a scalp biopsy is to be performed it is worth checking with a local pathologist as to what is required - some departments prefer two 4 mm punch biopsies, one each for horizontal and vertical sectioning
- In general the decision as to whether or not a biopsy is needed is best left to a specialist, who will also be in a better place to correlate the histology result and clinical findings should a biopsy be performed
Management
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Management depends on the clinical context - refer to the clinical findings and related chapters (above)
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Who to refer
- Patients with scarring alopecia should be considered for prompt referral to Secondary Care as once scarred the alopecia is irreversible
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Patients with non-scarring alopecia may also need referring as follows:
- Diagnostic uncertainty
- Some cases of alopecia areata
- Management issues eg trichotillomania
- If associated with moderate-severe emotional distress
- If a wig is required - wigs can be used as effective ways to cope with alopecia. Local dermatology departments may be the best contact in terms of obtaining / finding out where to obtain wigs on the NHS. Patients are given a choice of monofilament acrylic wigs or synthetic acrylic wigs. Human hair wigs are normally reserved for patients found on patch tests to be allergic to acrylic wigs
Other resources
- Patient support groups - Alopecia UK