Methoxsalen

Alopecia areata is an idiopathic, asymptomatic, nonscarring disorder characterized by single or multiple patches of well-demarcated hair loss (Figures 1 and 2). Males and females are equally affected; most patients are in the third to sixth decade. [1,2] Although the hair loss is usually localized, it is extensive in 10 to 30 percent of patients. [3] In alopecia totalis (Figure 3), patients lose all or nearly all scalp hair, while in alopecia universalis (Figure 4), patients lose all or almost all body hair, including scalp, eyebrow, beard, axillary and pubic hair.

Clinical Patterns

Alopecia areata begins with the sudden disappearance of scalp hair in one or more 1- to 3-cm round or oval patches. The initial patch may enlarge centrifugally, or multiple new areas of hair loss may appear over the next few months, with some patches coalescing into larger bare areas.

Progression of hair loss varies among individuals. Regrowth may occur spontaneously within a few months, or new bare patches may appear while older patches are regrowing. [4] Rarely, patients present with the sudden appearance of alopecia totalis or alopecia universalis. In 50 percent of cases, the duration of the first episode is less than one year, but 25 percent of cases persist longer than five years. [1] Usually, regrown hair is similar in color and texture to the surrounding normal hair, but in rare instances, it may be gray or white [5] (Figure 5).

Hairs characteristic of alopecia areata are often seen near the periphery of enlarging lesions. These short, broken hairs are tapered and lighter in color proximally, leading to the name "exclamation point" hairs (Figure 6). The classic histopathologic finding in alopecia areata is the presence of miniature hair structures. Early findings include a predominance of early anagen (growth phase) hairs, while in lesions of long duration, dystrophic telogen (resting phase) hairs or empty follicles are more prevalent. A variable inflammatory infiltrate within the dermis often invades the matrix of the hair bulb and the outer root sheath of early telogen hairs. The infiltrate is more intense in lesions of short duration, producing a "swarm of bees" appearance around the early anagen hair bulbs [6,7] (Figures 7 and 8).

The relapse rate in patients with alopecia areata can approach 100 percent. [2] Prognosis tends to be worse in patients with extensive alopecia areata and with onset of disease in childhood. [2,4]

Although an inheritance pattern has not been identified, approximately 25 percent of patients have a family history of alopecia areata. [7] Diseases found in association with alopecia areata include Down syndrome, atopy, thyroid disease (including Hashimoto's thyroiditis), vitiligo and pernicious anemia. [7] The role of psychologic stress in the pathogenesis of alopecia areata remains controversial. [7]

Nail changes, occurring in up to 60 percent of patients with alopecia areata, include shallow pits in a "grid" pattern (Figure 9), linear grooves, onychodystrophy, red nails and spotted lunulas. [8,9]

Differential Diagnosis

The differential diagnosis of alopecia areata includes tinea capitis, trichotillomania, traction alopecia, secondary syphilis, sarcoidosis, systemic lupus erythematosus, androgenic (male pattern) alopecia and telogen effluvium. Searching for "exclamation point" hairs may be worthwhile; punch biopsy, for histopathologic confirmation and fungal culture, is often indicated.

Treatment

Because of the possibility of spontaneous regrowth and the high incidence of relapse, evaluation of therapies used for alopecia areata is difficult. Table 1 lists some of the most commonly used therapeutic agents.

CORTICOSTEROIDS

Intralesional injection of corticosteroids remains the most popular therapy for patients with alopecia areata. [2,7] 10 Hair regrowth can be seen two to four weeks after a single injection into an affected area. The agent most often used is triamcinolone acetonide, in a concentration of 3 to 10 mg per mL; monthly injections can be given. Atrophy at the injection site is the only common side effect at concentrations above 4 mg per mL. Pain from injections can be reduced by using a small-gauge needle and by injecting the drug slowly.

Systemic corticosteroid therapy causes hair regrowth, but the regrowth is not maintained once the therapy is discontinued. [10] Prednisone, 20 to 40 mg per day orally, can be used to halt rapidly progressing hair loss. [10] The dosage should be tapered slowly in an attempt to maintain any regrowth. Topical corticosteroids are rarely successful in growing hair. Even the most potent topical preparations, such as clobetasol propionate (Temovate) or betamethasone diproprionate (Alphatrex, Diprolene, Lotrisone, etc.) are usually of little value. [10] A combination of intralesional, systemic and topical corticosteroids can be tried in resistant cases.

CONTACT DERMATITIS

An allergic contact dermatitis induced and maintained on the scalp results in hair regrowth in some patients with alopecia areata. The first agent that was used for this purpose was dinitrochlorobenzene (DNCB). [11] Patients are first sensitized to DNCB by applying a 2 percent concentration to the scalp or forearm. Two to four weeks later, weekly treatments are begun with the application of a .0001 to 2.0 percent solution of DNCB to the affected scalp areas to maintain a persistent, low-grade eczematous contact dermatitis without oozing or blistering. Hair growth is seen three to ten weeks after treatments are begun. [12] DNCB has been found to be mutagenic in the Ames test and may therefore be carcinogenic. [13]

Other potent contact allergens, such as squaric acid dibutylester (SADBE) and diphencyprone, have recently been evaluated in the treatment of alopecia areata. [14,15] These agents, which are not mutagenic in the Ames test, have an effectiveness similar to that of DNCB. Patients are sensitized and treated with these agents by the same method used with DNCB. Regrowth is seen in three to ten weeks. Side effects associated with the use of potent contact allergens include eczematous or urticarial eruptions and a burning sensation.

The use of anthralin (Anthra-Derm, Lasan, Dritho-Scalp, etc.) or other primary irritants to cause contact dermatitis has been successful in regrowing hair in patients with alopecia areata. [7,16] Anthralin can be used either in a high concentration for a brief period (up to one hour) daily-so-called "short contact therapy" -or in a lower concentration for eight to ten hours daily (usually overnight). Anthralin therapy also may be successful in children, with regrowth reported in up to 85 percent of cases. [10]

PHOTOCHEMOTHERAPY

Photochemotherapy with psoralen and ultraviolet A irradiation (PUVA) also can be used in the treatment of alopecia areata. [7] The psoralen (methoxsalen) can be given either orally or topically; the ultraviolet light can be administered locally or to the entire body. The patient is treated two to three times weekly until hair regrowth occurs. PUVA is generally limited to patients over age 12. Side effects include nausea with orally administered methoxsalen and burning erythema. Eye protection with ultraviolet-blocking glasses is necessary for patients receiving systemic methoxsalen therapy.

MINOXIDIL

Minoxidill (Rogaine), a potent vasodilator, has recently received much attention in the treatment of male-pattern baldness. Both topical and oral minoxidil therapy have been tried in alopecia areata. [17] Topically, concentrations ranging from 1 to 5 percent twice daily have been used. [17-19] In general, the response rate has b= around 10 percent, with recurrences of hair loss noted after treatment is discontinued.

Oral minoxidil may result in more extensive and more rapid hair growth, but cosmetically acceptable regrowth is seen in only 18 percent of patients. Adverse effects, including fluid retention, headache, depression, lethargy, palpitations and tachycardia, may make oral minoxidil an unacceptable mode of therapy for alopecia areata. [17]

IMMUNOSTIMULANTS

Recently, inosiplex (Isoprinosine), an investigational immunostimulant, has been used to treat patients with extensive alopecia areata and abnormalities in cellular immune function. Good results have been reported. [21]

Final Comment

Alopecia areata can be difficult to treat. The spontaneous remissions and frequent relapses complicate evaluation of therapeutic agents. Physicians must continue to give supportive treatment to patients with this cosmetically distressing disease. Therapy should be continuous until hair regrowth occurs, and concentrations and dosages of medications should be increased when necessary.

Support groups are available for patients with alopecia areata. Information can be obtained by contacting The National Alopecia Areata Foundation, 714 C Street, Suite 216, San Rafael, CA 94901, (415) 383-3444.

(Figures omitted)

COPYRIGHT 1990 American Academy of Family Physicians
COPYRIGHT 2004 Gale Group