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Etiam capillus unus habet umbram suam (Even a single hair casts a shadow)
Publilius Syrus
Hair loss carries with it a tremendous emotional and psychological burden for the patient.1 It can also be very daunting both diagnostically and therapeutically for the clinician. With entities ranging from Shokeir syndrome to citrullinaemia, the differential diagnosis of alopecia overwhelms at first blush. Fortunately, when we focus on children, especially otherwise healthy children with previously normal hair, the considerable number of possibilities falls precipitously and we are left with a not-so-daunting few.
In this review, we will focus on four of the most common causes of alopecia in children: telogen effluvium, trichotillomania, tinea capitis and alopecia areata.2 Although perhaps seemingly straightforward, there are a number of pearls and perils in sorting out these entities and selecting treatment that I hope to explore.
INTRODUCTION
Telogen effluvium refers to an abnormality of the normal hair cycle that results in excessive loss of telogen or resting-stage hairs.3 It is usually acute and self-limited and frequently occurs after an illness or stressful event, but can also be related to medications, child birth and thyroid disease.3
Trichotillomania (sometimes preferentially referred to as trichotillosis as the suffix mania can connote insanity4) refers to habitual hair pulling and may fall into the spectrum of obsessive-compulsive disorders or, perhaps, can be conceptualised as a type of addiction.5
Tinea capitis (ringworm of the scalp) is a highly-contagious dermatophyte fungal infection of the scalp and hair. Although the commonest cause of tinea capitis worldwide remains Microsporum canis, starting about 20 years ago in the USA and more recently in the UK, the epidemiology has shifted such that greater than 90% of cases are now caused by Trichophyton tonsurans.6
Alopecia areata is a common, usually patchy and often unpredictable loss of hair from the scalp and body.7 It is thought to represent an autoimmune process, likely with a genetic predisposition and an environmental trigger.8 Histopathologically it is characterised by lymphocytes around the hair bulb in a pattern resembling a swarm of bees.8
DIAGNOSTIC CONSIDERATIONS
History
One of the most dreaded “oh, by the way, doctor ...”9 moments at the end of a visit is when the concern is for alopecia, because a careful history is critical in guiding the diagnosis and can demand tremendous detail. For our purposes we will assume that the basic history is an otherwise healthy child with new-onset hair loss in the past year. From here, there are several important considerations.
A sense of the course of the alopecia is very helpful. A history of intermittent spots that then recover completely is essentially diagnostic for alopecia areata, while an itchy, flaking area that has slowly expanded would raise significant concern for tinea capitis. The type of hair loss experienced is also important. When the patient reports that hair seems to fall out in large clumps from everywhere on the scalp, this might suggest telogen effluvium, while eyebrow or eyelash involvement is generally limited to trichotillomania and alopecia areata. Other illness, stressors and a family history can also direct the diagnosis. A history of anxiety, depression or obsessive-compulsive behaviours might raise concern for trichotillomania. In table 1 four useful history questions to help separate each disease are summarised.
Physical
There are several helpful findings on physical examination that can confirm the diagnosis if present. Figure 1 shows a patch of alopecia areata. The skin in the area of alopecia is smooth and normal looking, without scaling, pustules or erythema. One can see multiple thin, pale hairs especially around the perimeter. In figure 2 we see a detailed image of the edge of the patch that nicely demonstrates “exclamation-point” hairs. These hairs, which are named because they taper more proximally to the scalp like a stylised exclamation point, represent the ever-weakening attempt of the follicle to form a hair shaft while under lymphocyte attack.10 When all of the scalp hairs are lost, it is deemed alopecia totalis; when all of the body hairs are lost as well, it is deemed alopecia universalis.11
Although it may appear similar initially, figure 3 demonstrates the irregular pattern of short and medium length, stubbly hairs that are of full-thickness and do not taper, indicative of trichotillomania.12 This patient plucked hairs and picked at her scalp during the visit.
Looking beyond the scalp is also critical. In addition to eyebrow and eyelash involvement in alopecia areata, there are also several nail findings in areata that, when present, support the diagnosis. In figure 4 the characteristic nail changes are seen. These so-called “Scotch-plaid” nails represent pitting and grooving of the nail plate.10 Unlike the more haphazard pitting seen in psoriasis, the pits and grooves in alopecia areata tend to be very organised and often involve more of each individual nail plate.
Tinea capitis has a number of manifestations including the grey type, which presents with circular patches of alopecia and marked scaling; the black dot type, which represent many broken hairs at the scalp being viewed end on; the diffuse scale type, with a widespread, dandruff appearance, and the kerion, a boggy tumour of the scalp, sometimes with pustules, shown in figure 5. Although Wood’s lamp examination (365 nm ultraviolet light) was historically helpful as M canis infection reveals fluorescence, the significant epidemiological change to T tonsurans infection has rendered this diagnostic tool much less useful as the latter does not fluoresce.13 Interestingly, the reason for this change also brings with it a change in the clinical presentation. M canis causes what is called an ectothrix type infection of the hair, meaning its fungal elements are on the exterior part of the hair shaft. T tonsurans, on the other hand, causes an endothrix type of infection with fungal elements inside the hair shaft where it is hidden from the Wood’s lamp and also is more likely to result in hair shaft damage and breakage. Clinically this breakage presents as the black dot form: multiple tiny broken hairs appearing as black dots on the scalp.13
Looking beyond the scalp, cervical lymphadenopathy can be a prominent feature in more inflammatory variants of tinea capitis and can support the diagnosis.13 Additionally, particularly at the start of treatment, an “id” (or “ide”) reaction can be seen on the body and can be mistaken for a drug hypersensitivity. The id reaction, sometimes called autoeczematisation, is a widespread response sometimes seen when there is a local area of inflammation. It frequently appears as small, juicy papules that are pruritic. The word likely comes from the Greek ides which refers to the son or daughter, conveying the idea of a family relationship.14
Telogen effluvium is perhaps the most elusive in terms of the physical examination; its hallmark is that everything is normal except for the number of hairs in the resting phase. Early on in the course of disease, thinning may not be apparent to the examiner, and that is where the hair pull test is very useful. Normally, about 10–15% of the hairs are in telogen phase. Therefore, when grasping about 40 hairs and pulling gently and evenly, fewer than 4–6 should be extracted with each pull. If this number or more are extracted and the hairs are truly telogen hairs (identified by the tiny depigmented bulb on the root end), then this would favour a diagnosis of telogen effluvium.15 There are two caveats to this, however: (1) hairs in the periphery of a patch of alopecia areata can also be more easily pulled and can mimic telogen effluvium in this test; and (2) if the hair is washed within 24 h before the hair pull, it can be falsely negative. This is because the act of washing can remove many of the telogen hairs that would have been gently removed by the hair pull.
The last physical finding is actually an important negative: there must be no scarring. All of these causes of alopecia are non-scarring (with the exception of tinea capitis when severe enough). Figure 6 depicts an area of scarring alopecia, in this case folliculitis decalvans.
Table 2 summarises the key physical examination findings to help distinguish between these causes of alopecia.
Laboratory testing
At times clinical tools will be insufficient to confirm a diagnosis and laboratory testing must be sought. Particularly in the case of suspected tinea capitis, a potassium hydroxide (KOH) preparation can be performed of the scalp scale and hairs, as seen in figure 7. However, this can be difficult and unreliable; in such cases, sending scale and hair for fungal culture is recommended before starting treatment.6 To obtain material for a culture one can scrape the affected areas with a blunt scalpel, a sterile brush or moistened gauze to gather affected hairs and scale and then place these in either a sterile specimen cup or directly onto fungal culture media if available.16
Although fungal culture is slow, expensive and may seem unnecessary in “classic” presentations of tinea capitis, I have encountered situations where systemic treatment was initiated without culture and the patient did not improve. This calls the initial diagnosis into question, but once started on antifungal treatment, future cultures or KOH preparations are unreliable. In such cases, or when there is scarring, or when the symptoms and signs simply do not seem to fit neatly into one of these categories, a scalp biopsy can be very helpful. Generally, these four entities are readily distinguished histologically. Were it not for the technical difficulty, cost and discomfort involved in the biopsy of a child’s scalp, this would likely be part of the standard approach.
If alopecia areata is suspected, evaluation of the thyroid is recommended. In a study by Kurtev and Iliev, 48% of children with alopecia areata had evidence of autoimmune thyroiditis. Their recommendation was to check thyroid size, function and antibody at the time of diagnosis and every six months thereafter.17 I confess that this number seems high to me and, in my practice, I have only seen a small number of children with thyroid involvement in alopecia areata. A study by Tan et al showed only a 2.3% incidence of thyroid disease in these children, which seems more in line with my experience of clinically significant disease.18
In the case of telogen effluvium without a clear trigger, one could consider screening for underlying illness by testing complete blood count, thyroid-stimulating hormone, anti-nuclear antibody (ANA) and erythrocyte sedimentation rate.2
TREATMENT CONSIDERATIONS
Once the diagnosis is secured, appropriate treatment can be selected. In the case of telogen effluvium, reassurance can be given that the hair will very likely fully recover without any treatment.19 Should it persist more than 3–6 months, further workup for underlying illness or alternative diagnoses should be undertaken.20
For trichotillomania, counselling and behaviour modification techniques seem to be most effective. I have found that if the problem persists after diagnosis and a frank discussion with the family, referral to psychiatry is indicated for more intense treatment.12 Specifically, a behavioural treatment known as habit-reversal therapy was shown to be the most effective intervention in a recent systematic review.21
Tinea capitis, once proven by culture or KOH, requires systemic treatment. Griseofulvin has been the treatment of choice for over 40 years.22 It is usually given at a dose of 10–25 mg/kg/day for 6–8 weeks.6 Having experienced treatment failures with lower doses and shorter courses, I tend to use 20 mg/kg/day for eight full weeks. There are promising data, however, that shorter dosing schedules (as little as two weeks) using itraconazole, fluconazole or terbinafine will work as well or better, and such shorter courses may bring increased compliance.22 For now, however, I use these medications only when griseofulvin has failed or is contraindicated, though future studies may well elicit change in this practice.
In order to decrease spread of the infection, and perhaps to speed its clearance, topical selenium sulphide shampoo or ketoconazole shampoo 2% can be added as an adjunct.23 24
The treatment of alopecia areata is more challenging. As the prognosis is uncertain at best, and it is a disease known for spontaneous remissions, it is very difficult to evaluate therapies.25 Despite this, several prognostic factors have been delineated as conveying a poorer outcome: family history of autoimmunity, history of atopy, severe hair loss, younger onset and nail abnormalities.26 Because of the chance for spontaneous recovery (perhaps as high as 80% within one year for more limited disease)27 and as there are no known disease-modifying treatments, it is often reasonable to use watchful waiting and reassurance initially. Should the alopecia continue to worsen or persist, a therapy can be considered. It is important to keep in mind, however, that there are no great treatments at this time and, for many patients, alopecia areata can be a roller coaster of improvements and setbacks. Moreover, for a disease that has essentially no ramifications for general health, the psychological impact of alopecia areata can be incredible, sometimes seemingly out of proportion for the tiniest patch. Because of this, I find it helpful to get the patient involved in a support group and/or counselling from the very first visit.
Given that alopecia areata represents an autoimmune attack on the hair follicle, two broad treatment approaches emerge. The first is an immune “shock therapy”, so to speak, by causing a contact dermatitis in the area of hair loss. The second is immunosuppression, locally or systemically, usually with corticosteroids.
Freyschmidt-Paul et al posit a very rigorous scheme for applying evidence-based medicine to the treatment of alopecia areata. In their review, they conclude that only contact sensitisation therapy (using chemical sensitisers such as squaric acid dibutylester) meets their standards of evidence.28 In this technique, the sensitiser is applied to an area and covered. In the case of squaric acid dibutylester, this can be a 2% solution. The area is observed over the next two weeks for a reaction that is often similar to poison ivy contact dermatitis. Once obtained, the individual is “sensitised” and a more dilute solution (a 0.001% solution of squaric acid, for example) of the sensitiser is applied to the areas of alopecia weekly, increasing in concentration until there is a mild dermatitis in the areas being treated.29 However, this treatment is not always easily available and can be unpleasant in the case of more severe reactions. Moreover, despite the excellent initial regrowth rate, there is a high rate of relapse, occurring in 81% of patients who initially responded in a recent study.29
Many non-randomised studies demonstrate impressive hair regrowth using systemic corticosteroids. However, more than half of the patients who have benefited will relapse when the corticosteroids are stopped.30 This, along with the fact that the side effect profile is unacceptable in the long term, makes systemic corticosteroids a poor option for the vast majority of cases.
Topical application of corticosteroids remains a common treatment, despite poor aggregate data of efficacy.28 Their ease of use, relatively low cost and limited side effect profile explain their continued widespread use.8
Intralesional injection of corticosteroids (triamcinolone acetonide, often at a concentration of 5–10 mg/ml) has the ability to cause rapid hair regrowth within 4–6 weeks with numbers as high as 97% achieving regrowth.8 However, the procedure can be painful, especially for younger children, and is impractical for larger areas of alopecia. Additionally, used in this way the corticosteroids can cause significant skin atrophy over time.27
Often left to an option of last resort, I find that recommending the use of hairpieces or wigs can be helpful even during treatment. It allows the patient to have coverage while therapy is being administered and, simultaneously, to get comfortable wearing the wig in the event that therapy fails. Many patients do not like this option, but mentioning it from early in the relationship seems to make it more palatable when needed. Treatment advantages and disadvantages are outlined in table 3.
CONCLUSION
Unlike a bump or a rash on the skin, with alopecia it is not “something”, but rather something that is missing. Patients can feel a tremendous loss with alopecia, yet thankfully for many cases the prognosis and treatment options are excellent (table 4). Even in those cases where treatments fail, the simple act of addressing the alopecia and empathising with the patient seems to go a long way towards helping make him or her feel whole.
REFERENCES
Footnotes
Competing interests: None.