genital ulcer( chancre), which, if untreated, may progress to sec- |
Intramuscular penicillin is the first-line treatment of choice. If con- |
The rash is not painful or itchy, and is a little raised.
disease. A biopsy of the skin lesion reveals a characteristic neutrophilic
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www. atlasdermatologico. com. br / disease. jsf? diseaseId = 173 |
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ondary syphilis. Symptoms of sec- |
traindicated, doxycycline has been |
infiltrate. 9 |
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ondary syphilis usually occur 4-10 weeks after the primary lesion and last 3-12 weeks. They include the |
shown to be effective, with a minimum course of 14 days. Specialist advice is recommended for cases |
Mpox is caused by poxvirus infection. It usually causes skin sores or lesions that progress through five |
What is the most likely diagnosis?
a Pseudomonal nail infection
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characteristic painless maculopapular, sometimes nodular, rash involving the palms and soles associated |
treated with non-penicillin therapies, as these have a less substantial evidence base. Urgent specialist |
distinct stages: from flat macular to papular rash, to vesicular lesions, to pustules that eventually scab. Diag- |
b Subungual haematoma c Subungual melanoma |
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with systemic symptoms such as fever, myalgia, headache and leth- |
input is also recommended for any antenatal infections. For pregnant |
nosis is usually clinical, with PCR as a confirmatory test. 10 |
d Onychomycosis |
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argy. These usually resolve spontaneously with or without treatment. However, without treatment, the affected individual is infectious for up to two years. The infection then progresses to a latent stage during which no symptoms are experienced. If syphilis is not treated at this stage, it may remain latent for life or progress to tertiary syphilis. 5 This develops in about one-third of people who have not been treated and can manifest up to 30 years after infection acquisition. In this stage, the disease may involve the CNS, cardiovascular system, viscera and joints, and can be fatal.
Re-infection may occur after effective treatment. Therefore, confirmatory serological tests are necessary in treated patients with new symptoms, to differentiate between new and previously treated infection.
Transmission typically occurs via direct sexual contact with an infectious lesion, or vertically to cause fetal infection. Contact with any open lesions with organisms present( typically the primary chancre, or secondary mucous patches or condylomata lata) can lead to a primary syphilis lesion at the site of inoculation, thus transmission may occur through kissing or touching active lesions at any mucosal or skin surface. Infectious lesions are highly contagious in the primary and secondary stages and the early part of the latent stage. The tertiary stage is not usually infectious.
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women with penicillin allergy, desensitisation and penicillin treatment may be required. 7
An abstinence period of a minimum of seven days post-treatment is recommended. Patients should be advised not to have sex with any partners from the past three months( if they have primary syphilis), six months( if they have secondary syphilis), or 12 months( if they have early latent syphilis) until these partners have been tested and treated if necessary.
Contact tracing and presumptive treatment of partners where last contact was within three months is indicated at minimum, with contact tracing up to 12 months back indicated, depending on stage of infection at diagnosis. 7 Treatment of partners is essential to prevent reinfection and spread. 6
Erythema nodosum and Sweet syndrome rash are usually tender, while Mpox sores have distinctive progressive inflammatory stages. Erythema nodosum usually presents with tender erythematous nodules confined to the lower extremities. It is seen in association with a wide variety of infectious and non-infectious inflammatory conditions and is thought to be immune-mediated. 8
Sweet syndrome, or febrile neutrophilic dermatosis, presents with fever and nodular skin lesions that ulcerate. The aetiology is unclear, but it is predominantly found in individuals with haematological malignancies or another underlying
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Outcome
Jack’ s case is discussed with the local infectious diseases team, who advise to proceed with a 14-day course of doxycycline.
Contact tracing and measures to avoid reinfection are discussed with Jack. He says he frequently travels for work and reports a few incidents where risky sexual activities took place while he was intoxicated; these are considered the most likely source of infection. He is counselled about safe sex practices to reduce the risk of reinfection post-treatment.
References on request from kate. kelso @ adg. com. au
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ANSWER The answer is a. This is a case of chloronychia, or green nail syndrome, secondary to Pseudomonas aeruginosa. The pathognomonic green discolouration occurs as a result of the pigments pyoverdine and pyocyanin, which are produced by the organism, adhering to the undersurface of the nail plate. 1, 2
P. aeruginosa is an opportunistic Gram-negative aerobic coccobacillus. It colonises naturally damp areas such as soil, water, plants and animals( including humans). P. aeruginosa takes advantage of defective barriers, such as broken skin or nail beds, which result from local trauma.
Predisposing factors include nail microtrauma, nail disorders, and regular handwashing or immersion. 2 Green nail syndrome is more common in certain occupational settings, such as barbers, dishwashers, bakers and medical staff, where workers’ hands consistently come into contact with water. 2 Immunocompromise is an additional risk factor. 1, 2
Additionally, acrylic nail use for more than one month increases the likelihood of green nail syndrome. It is thought this may be due to entrapment of water between the artificial and natural nail. 3
Typically, only 1-2 nails are involved. The characteristic nail discolouration may also be accompanied by a paronychial infection at the base or side of the nail or onycholysis of the distal nail. The characteristic green-yellow, green-blue or green-brown nail discolouration is sufficient for diagnosis, which can be microbiologically confirmed via culture of affected nail clippings. 2
Initial treatment with acetic acid 2 %( white vinegar diluted 1:1 with water) topically, soaking the nails for 5-10 minutes twice daily for 3-4 weeks is recommended. 4 Topical fluoroquinolone treatment may be required, with dermatology review recommended for treatment-resistant cases. 4
Preventive measures include limiting, or protection from, water immersion, and ensuring hands and nails are well dried after exposure, minimising nail trauma, and management of contributing medical factors( such as nail disease or immunocompromise).
Dr Kate Kelso is a GP and medical editor at Australian Doctor. References on request from kate. kelso @ adg. com. au
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