Hair loss has various etiologies. Correct diagnosis of hair disorders is complex and requires the evaluation of clinical presentation, history, physical examination, and laboratory test results. In the patient with a sexually transmitted disease (STD), alopecia may be an important associated finding and can provide clues to diagnosis. This review focuses on the relationship between hair loss and STDs. Specifically, we review alopecia in association with syphilis and human immunodeficiency virus (HIV) infection and the medications used to treat these infections. In addition, we review the literature regarding the putative association between alopecia areata and cytomegalovirus (CMV). There are multiple mechanisms involved in hair loss in these diseases, including the diseases themselves, systemic sequelae of these infections, autoimmune phenomena, and side effects of medications.
When considering the STDs associated with hair loss, syphilis is usually the first STD described because of the large incidence of the disease and its many reported cases of associated hair loss. This is especially important due to the increasing number of current cases of syphilis. Hair loss does not occur in primary syphilis except when associated with a primary chancre of scalp. Hair loss in secondary syphilis, also known as latent syphilis, occurs infrequently; various series report an incidence of 2.9% to 7%.1,2 There are 2 types of secondary syphilitic alopecia. The first is an uncommon symptomatic type found in association with an actual secondary lesion (usually papulosquamous) on the scalp. The second is termed essential syphilitic alopecia, which designates hair loss in the absence of visible syphilitic scalp lesions. Essential syphilitic alopecia has been divided into 3 types: the classic patchy "moth-eaten" alopecia (Figure), a generalized thinning of the hair, and the moth-eaten type in combination with general thinning of the hair. Of these, patchy moth-eaten alopecia occurs most frequently. The diffuse hair loss of essential syphilitic alopecia as the only manifestation of syphilis is uncommon. Cuozzo et al3 described 2 patients in whom the first sign of disease was alopecia.
Moth-eaten alopecia of syphilis is a characteristic manifestation of secondary syphilis that usually affects the scalp and occasionally other areas such as the eyebrows, beard, and pubic area.4 This form of alopecia may be confused with trichotillomania, traction alopecia, and alopecia areata.5 Pareek4 described a case of an unusual location of patchy moth-eaten alopecia that presented on the anterior side of the lower legs of a 30-year-old man in conjunction with patchy alopecia on the scalp and thinning of the eyebrows. With penicillin administration, hair of the legs, scalp, and eyebrows started to grow; the hair was fully regrown within 6 months, which suggests good prognosis with treatment instigation for syphilitic alopecia of all areas.
Jordaan and Louw5 systematically documented the histopathologic features of 12 patients with moth-eaten alopecia. Characteristic features included follicular plugging; a sparse, perivascular and perifollicular lymphocytic infiltrate; telogenization; and follicle-oriented melanin clumping.5 van der Willigen et al6 conducted a study of hair roots in 11 and 8 patients with primary and secondary syphilis, respectively. A decreased number of anagen hair roots; an increased number of catagen hair roots, dysplastic/dystrophic hair roots, and anagen hair roots with sheaths; and more than 20% angulation were observed in both groups.6 In addition, Lee and Hsu7 noted the histopathologic similarity between alopecia syphilitica and alopecia areata. They reported the histopathologic findings of alopecia syphilitica from 9 patients with secondary syphilis and acute hair loss. The alopecia was moth-eaten in 4 patients and was diffuse but slightly moth-eaten in 5. Microscopically, the dermoepidermal interface was not involved. The number of hair follicles was diminished, with increased numbers of catagens and telogens. Lymphocytic infiltration was present around the hair bulbs and fibrous tracts in 8 patients, and plasma cells were present in 4 biopsy specimens. Except for the follicular changes, the findings resembled those of macular/maculopapular syphilides outside the scalp. With the follicular changes, the overall patterns closely resembled alopecia areata. Results of the modified Steiner stain did not reveal spirochetes in any of the patients and failed to differentiate between alopecia syphilitica and alopecia areata. Comparing the alopecia syphilitica patients with 13 patients with alopecia areata, the authors found only a few differentiating features. They concluded that the presence of peribulbar eosinophils strongly suggests alopecia areata.7 Without peribulbar eosinophils, the presence of plasma cells, abundant lymphocytes in the isthmus, or peribulbar lymphoid aggregates suggests alopecia syphilitica. Elston et al8 observed several cases of syphilis with numerous eosinophils in the peribulbar infiltrate and noted that it can be indistinguishable from alopecia areata.
When an associated skin rash or lymphadenopathy is present, the diagnosis of syphilis may be suggested and confirmed by positive serology test results. If such findings are not present, a biopsy specimen to differentiate from other forms of alopecia should be obtained. Because moth-eaten alopecia and alopecia areata have similar resemblance microscopically, syphilis serologic tests are needed.
The treatment of syphilis also has been shown to be a cause of alopecia. Pareek9 described the association of syphilitic alopecia and Herxheimer reaction. A 25-year-old man presented with syphilis with widespread thinning of the scalp hair, eyebrows, and pubic area; the scalp showed patchy moth-eaten alopecia. He was treated with 1 to 2 megaunits of procaine penicillin daily for 10 days. Six hours after the first injection, the patient's temperature rose to 103°F; in addition to malaise, headache, flush, and sore throat, he had a transient skin rash and marked loss of hair. All the symptoms disappeared by the next day. Two to 3 weeks later, the lymphadenopathy had disappeared, and the patient's eyebrows and pubic hair started to regrow. The scalp hair was fully regrown 10 weeks from the onset of treatment. The author concluded that diffuse and extensive hair loss after the first injection of penicillin was part of the Herxheimer reaction.9