Chancroid (Ulcus Molle, Soft Chancre)

Introduction

Chancroid is an infectious disease caused by Haemophilus ducreyi, a small gram-negative bacillus.
It is common in the tropics, especially in Africa, the Far East, and the Caribbean.
Persons may present with chancroid outside endemic regions; sporadic outbreaks of infection occur in Europe and North America.

Clinical features

  • Incubation period is about 3-7 days
  • It begins as a small, tender papule, changing into a pustule which rapidly progresses to a painful ulcer with a bright red areola.
  • Neither the edge nor base of the ulcer is indurated (unlike syphilis)
  • The ulcer feels soft, hence the name ‘soft sore’ (ulcus molle)
  • With superimposed bacterial infection, it often feels indurated
  • Sites of predilection in men are the prepuce, frenulum, glans or shaft of the penis
  • The ulcers may be multiple due to auto inoculation
  • In women the labia, fourchette, vestibule, clitoris, cervix, or perineum are favored sites.
  • Lesions may cause dyspareunia, pain on voiding or defaecation and vaginal discharge
  • Women may be asymptomatic carriers
  • About 7 – 14 days after the appearance of the ulcer, a bubo appears
  • A mass of gland smatted together, of tenad herent to the overlying skin
  • The glands above the inguinal ligament are usually affected, and often there is a unilateral enlargement.
  • Central softening is often found and if untreated the bubo may rupture and discharge through a fistula
  • The combination of a painful genital ulcer and suppurative inguinal adenopathy is almost pathognomonic of chancroid
  • Patient may present with bubo, the initial ulcer having healed
  • Atypical lesions have been reported in HIV infected individuals
  • More extensive, or multiple lesions
    sometimes accompanied by systemicmanifestations such as fever and chills

Complications

  • Progressive ulceration and amputation of the phallus, particularly in HIV patients

Differential diagnoses

  • Other causes of genital ulcers: Syphilis
  • Herpes
  • Granuloma inguinale
  • Lymphogranuloma venereum
  • Fixed drug eruption
  • Erythema multiforme
  • Behcet’s disease
  • Trauma
  • Tuberculous ulcer
  • Cancers

Investigations

  • Microscopy, culture and sensitivity of discharge from ulcer
  • Serological tests e.g. complement fixation (CF); microimmuno-fluorescence (MIF) test; PCR

Treatment objectives

  • Eliminate the organism in the patient and sexual partner(s)
  • Prevent re-infection
  • Prevent complications
  • Counsel and screen for possible co-infection with HIV so that appropriate management can be instituted

Drug therapy

Recommended regimen:

  • Ciprofloxacin 500 mg orally every 12 hours for 3 days

Or:

  • Erythromycin 500 mg orally every 6 hours for 7 days

Or:

Azithromycin 1 g orally as a single dose
Alternative regimen:

  • Ceftriaxone, 250 mg by intramuscular injection, as a single dose

Adjuvant therapy

  • Keep ulcerative lesions clean
  • Aspirate fluctuant lymph nodes through the surrounding healthy skin, preferably from a
    superior approach to prevent persistent dripping and sinus formation
  • Incision and drainage, or excision of nodes may delay healing and is not recommended

Follow-up

  • All patients should be followed up until there is clear evidence of improvement or cure
  • In patients infected with HIV, treatment may appear to be less effective, but this may be a
    result of co-infection with genital herpes or syphilis
  • Chancroid and HIV infection are closely associated and therapeutic failure is likely to be seen with increasing frequency
  • Patients should therefore be followed up weekly until there is clear evidence of improvement

Notable adverse drug reactions, caution and

contraindications
Ciprofloxacin and ceftriaxone (see
gonorrhoea)
Erythromycin and azithromycin (see
chlamydia)

Prevention

Counselling, Compliance, Condom use and Contact treatment.