Published on 18/03/2015 by admin
Filed under Dermatology
Last modified 18/03/2015
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Eavan G. Muldoon and Derek Freedman
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Syphilis is an ancient disease that many mistakenly believe to be on the decline. A century ago, Osler said ‘Know syphilis in all its manifestations and relations, and all things clinical will be added unto you.’ Syphilis’ manifestations are protean, hence the reason it is often known as ‘the great impostor’ or ‘great pretender.’ Syphilis facilitates the transmission of human immunodeficiency virus (HIV) by a number of mechanisms, including increasing HIV viral load, disruption of the mucous membrane barrier and increased HIV shedding. Prompt recognition and treatment have significant public and personal health benefits. Syphilis is an indicator disease for HIV, and a syphilis diagnosis provides opportunities for the screening and early diagnosis of HIV, which will have impact on patients’ prognosis and further transmission.
Men who have sex with men (MSM), commercial sex workers, or patients from areas of the world where there is a high prevalence of syphilis have a higher risk of syphilis acquisition. A thorough history is essential and may uncover past potential risks that may not be immediately evident, such as woman with past partners who are MSM. However, many are unaware of their risk status, and routine testing is required.
Transmission of syphilis is by direct contact with an infectious individual. Sexual contact is the most common mode of transmission. However, in the current era of so-called ‘safer sex practices’ transmission by kissing, or other close contact with an active lesion, such as oral sex, have become more common. Transplacental transmission, blood transfusion or accidental inoculation can all also rarely occur.
The appropriate management is determined by the stage of syphilis infection. Infection is divided into:
Incubation period
Primary syphilis characterized by a primary chancre(s)
Secondary syphilis
A period of sub-clinical infection or latent syphilis
Tertiary syphilis, which does not occur in every patient
The patient is most infectious in the early stages of disease, particularly when the primary chancre, mucous patch or condyloma lata are present. An immunologically intact person cannot spread syphilis after 4 years of infection.
Treponema pallidum penetrates the intact mucous membrane or gains access through abraded skin. Within hours to days it enters the lymphatic system and/or bloodstream and disseminates throughout the body. This occurs soon after contact; patients have been infected by blood transfusions from donors with negative serology who are in the incubation period. The incubation period is directly proportional to the size of the inoculum: in rabbit models as few as four to eight spirochetes are needed to establish infection. The median incubation period is 3 weeks, but can vary from 3 to 90 days.
Classically, a primary chancre is described as a single painless papule that occurs at the site of inoculation. The site of a chancre is not limited to the genital region. Any area where contact with an infectious lesion has occurred can be involved. The mouth and anal area are common extragenital sites (see Figure A).
The chancre appears after the incubation period, erodes and becomes indurated. The base is usually smooth, and the borders raised and firm with a cartilaginous consistency. The ulcer has a clean appearance with no exudate, unless it is super-infected. It is usually round; however, it may be oblong following tissue lines. There is little pain or bleeding when the ulcer is scraped, as may occur while obtaining samples for dark-field microscopy. Multiple chancres can occur, particularly in the setting of HIV infection. Atypical lesions are said to occur in 60% of patients, and many patients may have no primary lesion. The appearance of the lesion depends on the size of the inoculum, the immune status of the patient, and concurrent antibiotic usage. Regional lymphadenopathy of moderately enlarged, firm non-suppurative painless lymph nodes frequently accompanies the primary lesion.
The differential diagnosis of a primary chancre is herpes simplex, chancroid, and traumatic super-infected lesions. Other diagnoses that should be considered are early warts caused by human papilloma virus, granuloma inguinale, tuberculosis or atypical mycobacterial infections. Perianal lesions may be dismissed as hemorrhoids.
Secondary syphilis occurs when the spirochete multiplies and disseminates throughout the body. It lasts until a sufficient host response develops to control the organism. It begins 2 to 8 weeks after the appearance of the chancre; however, this is highly variable and the signs of primary and secondary infection may overlap. Many patients presenting with secondary syphilis, do not recall a primary chancre. The manifestations of secondary syphilis are protean.
The most commonly recognized signs of secondary syphilis are dermatological. The rash of secondary syphilis may be macular, maculopapular, papular, pustular or a combination of the above. Vesicular lesions occur only in congenital syphilis. Skin lesions usually begin on the trunk and proximal extremities. Classically, they are pink-red macular lesions 3–10 mm in diameter. Any surface area can become involved. The rash can last from a few days to up to 8 weeks. The lesions may evolve into papules and in some patients into pustules, when they are known as pustular syphilids. All types of rash may be present at the same time and the rash can involve any body surface. Palmar and plantar rashes (see Figure B) are highly suggestive of syphilis. Fever can accompany the rash, and the clinical syndrome can be mistaken for acute HIV infection, infectious mononucleosis or a non-specific viral syndrome.
Alopecia occurs when the hair follicles become involved. In warm moist areas, such as the genital and perianal areas, inner aspects of the thighs, the skin under breasts, nasolabial folds, axilla, antecubital fossae, and webs of fingers and toes, the papules can coalesce and erode resulting in painless, broad, gray-white, highly infectious plaques called condylomata lata. They can be mistaken for warts or hemorrhoids. Lesions may also develop on mucous membranes where they are called mucous patches. Associated enlargement of the epitrochlear lymph nodes is a unique finding that should always suggest the diagnosis.
Neurosyphilis, i.e., syphilitic infection of the central nervous system, can present at any time after infection. It can be classified into early and late disease. Early in the course of syphilis most forms of neurosyphilis will involve the cerebrospinal fluid (CSF), meninges and vasculature, while later disease that occurs in tertiary syphilis tends to affect the brain parenchyma and spinal cord. Currently neurosyphilis is most common in patients with HIV infection, and these patients almost exclusively have the early forms of neurosyphilis, often presenting as concomitant eye disease. Ocular syphilis is part of the clinical spectrum of neurosyphilis, and the initial presentation may be to an unsuspecting ophthalmologist. The presentation of ocular involvement is varied, the most common presentation being uveitis.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
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