White : Diseases of the Skin - Disorders of Hair

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Gary M. White & Neil H. Cox

Diseases of the Skin

28	Disorders of Hair

ALOPECIA AREATA

Alopecia areata (AA) is a common cause of either localized or generalized hair loss, and is discussed as a separate topic. Specific named variants of this condition, discussed here, include the following.

•	Alopecia totalis—loss of all the scalp hair.
•	Alopecia universalis—loss of all body hair.
•	Ophiasis—confluent hair loss on the occipital and parietal scalp.

Etiology and pathogenesis

In AA, the immune system, for some unknown reason, causes the hair to fall out in a well-defined area, usually on the scalp (Figs 28.14 – 28.20). This is thus an autoimmune condition. Why one area is chosen, what the trigger is, and what will determine whether the condition progresses or regresses promptly are unknown.

Most patients are entirely healthy, and the hair loss is an isolated finding (Fig.28.20). However, in large series, associated diseases have included
the atopic diathesis, Down syndrome, thyroid abnormalities (especially in children), and pernicious anemia. Stress is usually not a convincing precipitating factor. Screening for autoimmune conditions in the absence of symptoms is not felt to be necessary. A recent study indicates that antibodies to hair follicles present in most individuals with AA are heterogeneous and target multiple structures in hair follicles.

Clinical

The classic patient with AA is a teenager or young adult with one or more discrete, round areas of non-scarring alopecia, most commonly affecting the scalp (Figs 28.14 and 28.15). Hair loss can also affect the eyebrows, eyelashes, beard (Fig.28.16), and elsewhere. Short, blunt-ended hairs tapered at the base (termed exclamation mark hairs) may be seen near the margin of the alopecia. Regrowth tends to occur over months to a year. The initial regrowing hair is occasionally white (Fig. 28.17). When this happens, normal pigmentation may return shortly or may take many years.

Fig. 28.14 Classic appearance of alopecia areata. The patient presents with one, two, or three partially or completely bald round to oval areas. The skin appears completely normal.

Fig. 28.15 Exclamation mark hairs in alopecia areata (AA). Short, blunt-ended hairs tapered at the base (exclamation mark hairs) may be seen near the margin of the alopecia. These are diagnostic of AA.

Occasionally, other patterns of hair loss besides the typical round or oval pattern may be seen. For example, a reticular pattern, an ophiasis pattern, and, rarely, a diffuse form mimicking male pattern androgenetic alopecia have been reported. When all the scalp hair is lost in AA, the term alopecia totalis is used (Fig.28.21). When all body hair is lost, the term alopecia universalis is used. The physician must be sensitive to the psychologic distress that may occur with the loss of all one's hair (Fig. 28.22).

Fig. 28.16 Alopecia areata of the beard. Bald patches may occur on the beard. Note that the skin texture appears completely normal.

Fig. 28.17 White hair regrowth in alopecia areata. If untreated, regrowth tends to occur within 6–12 months. When it does regrow, the hair is often white initially.

Fig. 28.18 Nail pits in alopecia areata. Pitting of the nails may be an associated finding and is more common in advanced cases. The pitting tends to be uniform, whereas that of psoriasis is more sparse and haphazard.

Fig. 28.19 Cadaverized hairs in alopecia areata. These are soft, dystrophic stumps of hair. The pattern may resemble that of ‘black dot’ tinea capitis (compare with Fig. 28.27).

Fig. 28.20 Advanced alopecia areata. Most patients fear loss of most or all of the hair. This pattern of advanced disease is uncommon.

Fig. 28.21 Alopecia totalis with erythema nuchae.

Fig. 28.22 Alopecia totalis: eyebrows and eyelashes. The eyebrows and eyelashes are actually quite functional. The patient with alopecial totalis or universalis will complain of eye irritation. Debris is much more likely to enter the eyes, the sun’s rays are more bothersome, and sweat will often run straight from the forehead into the eyes.

Recently, a new subtype of AA (acute diffuse and total alopecia of the female scalp) has been described, where the woman suffers complete hair loss within 1 month of presentation. The histology is that of AA except for a significant eosinophilic tissue infiltrate. Fortunately, the vast majority of these women do well with cosmetically acceptable hair regrowth at 6 months with or without steroid administration.

In exceptional cases, only rarely reported, a patient with both dark and gray hair may lose only the pigmented hair. When diffuse, this may give rise to fantastic stories of the hair turning white overnight (although, in truth, it usually occurs over several days or weeks). This is actually explained by the immune attack occurring at the point in the hair cycle at which pigment is being incorporated, thereby sparing the white hairs.

In some patients, uniformly distributed pits may be seen on the nails (Fig. 28.18).

Differential diagnosis

See Table 28.3. Note that the differential diagnosis of the localized form of AA applies to patchy, non-inflamed, and non-scarring alopecia generally.

Treatment

For those with localized patches, reassurance may be the best treatment, as it has no side effects, and regrowth in untreated patients occurs in the vast majority by 1 year. Patients should be counseled not to scratch, as the remaining hairs are often very weak and break off easily. For those with localized patches who desire treatment, triamcinolone (2.5–5.0mg/mL intralesionally every month) is the most reliable way of regrowing hair. The hair bulbs are found about 2mm below the surface in AA, and this is where the medication should be directed. Deeper injection will miss the target and may cause lipoatrophy. Higher response rates are obtained with injection of hexacetonide, but there is a higher rate of atrophy. Some recommend mixing triamcinolone and hexacetonide. Potent topical steroids may be considered in children who may not tolerate injections, or in those with wider areas of loss in whom multiple injections may not be very practical.

Poor prognostic indicators for regrowth include duration greater than 5 years, prepubescent onset, alopecia totalis or universalis, and the ophiasis pattern. Some studies have shown the presence of nail pits to be an adverse prognostic factor.

Therapy for more widespread AA, such as alopecia totalis or universalis, may be difficult. Observation, acceptance, and the use of a wig are alternatives. The eyebrows may be injected (e.g. triamcinolone 2.5–5.0mg/ mL, after discussing the low risk of ocular complications). Pulsed oral prednisone, at a dose of 300mg orally every 4 weeks, has been advanced as safe and effective, although there is clearly potential for toxicity. It has worked most effectively in men and in those with AA for less than 2 years. Nausea and diarrhea were the only side effects seen in 32 patients. Anthralin ointment for 20–30min every day (short-contact therapy) to induce an irritant dermatitis may be tried.

Table 28.3 DIFFERENTIAL DIAGNOSIS OF ALOPECIA AREATA

Pattern	Disorder	Differential features
Localized patchesa^a	Trichotillomania	Hairs in trichotillomania are rarely totally absent. Usually the shortest hairs are 3–10 mm. Because some patients with AA may scratch (there may be some itch in active lesions) or may fiddle with their hair, there are some individuals who develop a diagnostically difficult combination of trichotillomania complicating AA.
	Temporal triangular alopecia	Triangular patch of vellus hair at the temples of a child, no other sites affected and not hairless.
	Monilethrix	May cause very sparse and short hair, especially occipital, but not hairless.
	Pseudopelade	This is actually a scarring alopecia, most common in women, and should therefore be readily distinguished.
	Tinea capitis	The black dot type can be relatively uninflamed.
	Secondary syphilis	Look for ‘moth-eaten’ alopecia.
	Other scarring alopecias (see Table 28.4)	These are less likely to be confused with AA.
Ophiasis	Frontal fibrosing alopecia	May suggest the ophiasis pattern of AA but is limited to the forehead.
More diffuse forms	As Table 28.1	Androgenetic alopecia (either sex), sex hormone abnormality in women, telogen effluvium, drug-induced loss, iron deficiency, thyroid disease, acute connective tissue disorders.

^aThe differential diagnosis of this pattern applies to patchy, non-inflamed, and non-scarring alopecia generally.

The application of various agents (e.g. diphencyprone and squaric acid) to induce an allergic contact dermatitis has been used, termed contact immunotherapy. Diphencyprone (diphenylcyclopropenone) is non-mutagenic in the Ames assay and is probably the most widely used. It is applied once weekly over a period of months at concentrations that cause a low-grade contact dermatitis; results are reasonably good initially (50–60% worthwhile response), but most studies suggest less than 30% long-term success, and response in more severe alopecia totalis or universalis is less than 20%. These agents may produce severe contact reactions, and in pigmented skin may cause hyper- or hypopigmentation; they have to be handled with great care to avoid inducing contact reactions in the healthcare team as well, so use is often limited to centers with experience in their use.

Other modalities include whole body or topical PUVA twice a week for 6–12 months, topical minoxidil, a 6-week course of prednisone combined with minoxidil (2% three times a day), and oral corticosteroids (e.g. intramuscular or oral, tapered to the lowest effective dose; side effects may be significant; it can be combined with topical and intralesional therapy). One study found PUVA ineffective for severe AA and questioned whether any treatment is effective. Isoprinosine potentiates T-lymphocyte and phagocyte function and has been used for treatment of AA.