STIs

Question 1

Syphilis cutaneous manifestations (13)

Answer 1

Primary - painless chancre - oral, genital or anywhere on skin

Secondary
Alopecia
Split papules oral commissure
Mucous patches mouth
Necklace of Venus (hypopigmented macules)
Mac/pap
Pap/nod
Pap/squamous
Trunk, extremities
Palms soles
Brown/copper macules
Clavus like lesions (corn like)
Small plaques w collerette of scale (collerette or biett)
Anogenital - Condylomata lata
Gummas

Question 2

Tests for syphilis

Answer 2

Treponemal - indefinitely positive, can see if has had syphilis or not any time. Positive at 10-90days.
False positive in HIV, autoimmune diseases, hypergammaglobulimemia

Non-treponemal - non-specific
RPR, VDRL. Titres correspond with disease activity, reduce by 4 fold with good treatment.
Measure of cell damage
False positive: infections including flu, HIV, EBV, measles, chickenpox, Covid-19 and pneumonia

PCR on swab or fresh tissue
Dark ground microscopy to visualise spirochètes

Question 3

Name of syphilis specific skin signs

Answer 3

Collerette of biett
Clavus like lesions
Condylomata lata
Mucous patches
Necklace of venus
Fausse perleche (false chelitis, split syphilitic papules)

Question 4

Treatment for syphilis

Answer 4

Early <1year
Ben pen 2.4MU IM stat dose
Or
Doxyc 100mg BD 14 days
OR azithromycin 2g Po one dose

Late >1year
3 doses Ben pen
OR
Doxyc for 28 days

Neuro/ocular syphilis
IV aqueous pencillin
OR ceftriaxone 14 days

Question 5

Syphilis treatment for pregnancy and neonatal

Answer 5

Pregnancy
Ben pen IM 2.4MU 2 doses wkly (early) or 3 doses (late)

Neonatal
Aqueous penicillin IV

Question 6

Stigmata congenital syphilis?

Answer 6

Cutaneous
Rhagades - radial periorificial scars

Dental
Hutchinson peg shaped teeth
Caries
Mulberry molars

Skeletal
Saddle nose
Frontal bossing
Hypoplastic maxilla
High palate
Tibial bowing
Thickening clavicle
Scaphoid scapulae
Effusions knees

Eyes/ears
Deafness
Keratitis - corneal ulcers and opacities

Question 7

Natural history of syphilis

Answer 7

Stages of syphilis
• Inoculation
• After on average 3 weeks, primary syphilis (chancre)
• 3 - 10 weeks after apperance of chancre, development of secondary syphilis
• Patients can then develop early, non-primary, non-secondary syphilis
○ 12 months from contact
• Patients can develop unknown duration or late syphilis
○ > 12 months from contact
• Neurosyphilis, otic syphilis and ocular syphilis can occur during any stage after infection
• Congenital syphilis - can occur if infection in mother from contraception to 7th month
Previous classification: secondary, latent, tertiary

Question 8

Histology syphilis

Answer 8

Ulceration
Diffuse dermal inflammatory infiltrate: plasma cells, lymphocytes, histiocytes
Can be perivascular, lichenoid, nodular, diffuse.
Anti-treponema pallidum antibody stain shows long twisted spirochètes

Can also be vasculitic in lues maligna or granulomatous in tertiary syphilis

Question 9

Tx MPOX

Answer 9

Tx: supportive care (analgesia, stool softener, topical lidocaine, tx hiv), tecovirimat

Vax:
Post exposure vax 4-14 days of exposure

Question 10

Syphilis workup

Answer 10

Swab PCR
Biopsy – histo/culture/pcr, syphilis IHC stain

Syphilis serology
HIV, Hep B/C, QFTB
Other STI screen – chlamydia, gonorrhoea

Lumbar puncture, MRI
ECG, Echo

Question 11

Oral cutaneous manifestations of HIV

Answer 11

CD4 350-500
1. Herpes zoster
2. Onychomycosis
3. Seb derm
4. Angular chelitis
5. Pruritic papular eruption
6. Recurrent oral ulcers
7. Warts
8. Molluscum
9. Linear gingival erythema

CD4 200-350
1. Persistent oral candida
2. Oral hairy leukoplakia
3. Acute necrotising ulcerative stomatitis/gingivitis

CD4 <200
1. Chronic HSV
2. Kaposi sarcoma
3. Cryptococcus inf
4. Disseminated endemic mycosis (coccidiodomycosis or histoplasmosis)
5. Disseminated non-TB mycobacterium
6. Atypical leishmaniasis

Question 12

Antiretroviral treatment interacts w which derm meds

Answer 12

ART interactions w itraconazole, retinoids

Question 13

Mpox symptoms

Answer 13

Prodrome 7-10days
Fever, headache, malaise, lymphadenopathy, myalgia
Painful rash 10-150 lesions face, trunk, extremities
Umbilicated, ulcerated pustulovesicular rash

Compl:
Sepsis, pneumonia

Question 14

Risk factors for severe disease MPOX

Answer 14

RF for severe disease:
Immunosuppression, AIDS, solid organ transplant, Pregnancy, young children

Question 15

5 treponema diseases

Answer 15

1. Venereal syphilis
2. Yaws
3. Endemic syphilis bejel
4. Pinta
5. Periodontal disease

Question 16

Organism syphilis

Answer 16

Treponema pallidum

Question 17

Organism gonorrhoea

Answer 17

Neisseria gonorrhoeae

Question 18

Gonorrhoea treatment

Answer 18

Cephalosporins
Cetriaxone 500mg IM single dose

Question 19

Infectious causes genital ulcers

Answer 19

HSV
Syphilis
Chancroid
LGV
Donovanosis

Question 20

Painless genital ulcer DDx

Answer 20

Syphilis
LGV

Question 21

Organism Chancroid

Answer 21

Haemophilis ducreyi