31. DMD Exanthems 2025

Exanthems, STIs and Infections in Pregnancy

Learning Objectives

• Describe the infectious risks associated with childhood exanthems.

• Examples of STIs leading to genital ulceration or mucosal/urethral inflammation.

• Pregnancy features increasing susceptibility to infection.

• Infectious targets in antenatal infectious disease screening program.

• Appropriate specimens/tests for infections.

childhood exanthems - VZV, measles, scarlet fever, rubella, Erythema Infectiosum (fifth disease)

Chickenpox (Varicella Zoster Virus)

• Incubation Period: 15 days., shedding for 24 hours before rash starts

• may june, droplet infection, very infectious

• Symptoms: rash, disseminated infection, pneumonia, encephalitis, congenital varicella.

• reactivation as shingles

• Diagnosis: PCR test for VZV, serology helpful at later stages (IgM, IgG).

• Immunization: Aciclovir for treatment/prevention; immunoglobulin for prevention.

Complications of Varicella

• Pneumonia: inflamation in lung, air sac with fluid. Particularly severe in pregnant and immunocompromised individuals.

• Congenital Varicella Syndrome: Fetus infected in utero

• Encephalitis: inflammation and swelling in brain

• vesicular intraoral lesions, chickenpox palatal lesions

Shingles (Zoster)

• Occurs due to reactivation of varicella zoster virus.

Measles

• Incubation Period: 10 to 14 days.

• Symptoms: runny nose, cough, conjunctivitis (pink eye), maculopapular rash, high fever. FERBILE RASH

• Koplik's spots - clustered white lesions on buccal mucosa 2 days before rash

• Complications: miscarriage, pneumonitis, encephalitis, subacute sclerosing panencephalitis (SSPE).

• Diagnosis: Direct detection of viral RNA using swab, IgG testing, oral fluid sample , MMR vaccination 2 dose - Measles, mump rubella all droplets

• high risk in infants, pregnant woman, immunosuppression

Scarlet Fever - GAS

• sore throat, like sand paper rash , characterized by a fine pink-red rash, fever, strawberry tongue

• Complications: rheumatic fever, rheumatic heart disease, acute glomerulonephritis.

• Diagnosis: throat culture for Streptococcus pyogenes (GAS), ASOT serology test.

• Treatment: Penicillin or Erythromycin

Rubella - rubella virus

• Incubation Period: 14-21 days.

• Symptoms: cold-like symptoms (sore head, runny nose), red-pink rash, swollen glands.

• spread through droplets

• Diagnosis: Rubella IgM test; prevention via MMR vaccine.

• Congenital Rubella Syndrome: Infection <15 weeks gestation孕期 can cause severe fetal damage, including eye problem, deafness, heart abnormalities, brain damage

Erythema Infectiosum (Fifth Disease)

• parvovirus B19

• Incubation Period: 4-20 days.

• Symptoms: mild illness, "slapped cheek" appearance, lace-like rash.

• in young children during spring

• Diagnosis: B19 IgM, PCR for pregnant women; fetal tissue PCR.

• Risks: fetal loss and hydrops fetalis.

Sexually Transmitted Infections (STIs)

• Mucosal/Skin Infections:

• Urethritis and cervicitis caused by Neisseria gonorrhoeae and Chlamydia trachomatis. → oral sex, transmit to the mouth → Cause oropharyngeal infection

• warts - human papilloma virus HPV

Complications -

• Chlamydia and Gonorrhea: can lead to pelvic inflammatory disease, persistent urethrits, septic arthritis, conjunctivitis.

• Antimicrobial Resistance: Gonorrhea particularly challenging due to growing resistance.

• Skin Ulcers: (genital or the mouth)

• caused by HSV-1/HSV-2 and syphilis

• HSV1/2 - in the mouth → cold sores. Primary infection → gingivostomatisis (sores in gums) recurrent infection - herpes labialis at the same place

• Syphilis (caused by treponema pallidum) - primary chancre - painless ulcer in mouth or genital area

• secondary syphilis - mocosal lesions spread to systemic infection, snail track ulcers

Laboratory Diagnoses for STIs

• Serology: blood tests for syphilis, BBV (HIV, HBV, HCV)

• PCR: for urethritis and cervicitis (clamydia and gonnorrhoea) swab or urine

• 

Pregnancy and Infection

• Increased infection Susceptibility: Immunosuppressed state and physiological/anatomical changes in pregnancy.

criteria for a good screening program BIRS

• condition severeness, natural history (symptons, how it spead, what it does to body), detectabel stage, availability resources, risk less than benefit

• Key diseases: HIV, HBV, Syphilis, Rubella. - they meet all the criteria

Antenatal Infection Screening Program - related to pregnancy

• Screen for: HIV, HBV, Syphilis, Rubella (immunity).

• Use serology blood tests.

Antenatal Screening

• Tests offered for every pregnancy, results in 10 working days, referred clinic will arrange additional blood test if abnormal is found

• if after 24 weeks of pregnancy, results are urgent, test in 24 hrs

• if in labour and not screened → urgent test for HIV, HBV, syphilis

• test should be offered again before 28 weeks of pregnancy if initial offer was declined by pregnant pers

• store aliquot at -20 for 2 years

Common Infections in Pregnancy

• Includes: Syphilis, HIV, HBV, Rubella, Toxoplasma gondii, Cytomegalovirus, Parvovirus B19, Varicella, several herpes types, E.coli, group B streptococcus.

Effective Interventions for Antenatal Infections

• HIV: HAART therapy, C-section considerations, avoid breastfeeding.

• Syphilis: Penicillin treatment.

• HBV: Antiviral medications, vaccinations.

• Rubella: MMR vaccination 2 dose postnatally.

• For all infections: surveillance, monitoring, and treatment options as necessary.