A36.3 Cutaneous diphtheria

Name of the Condition

• Cutaneous diphtheria

Summary

Cutaneous diphtheria is a localized form of diphtheria affecting the skin. It is caused by Corynebacterium diphtheriae and is characterized by the formation of non-healing ulcers or lesions at the site of infection. The infection may also produce a potent exotoxin that can lead to systemic complications, even if the primary site is limited to the skin.

Causes

Cutaneous diphtheria is caused by infection with Corynebacterium diphtheriae, a gram-positive bacterium. The disease spreads through direct contact with an infected person’s skin lesions or contaminated objects. The exotoxin produced by the bacteria is responsible for tissue damage and potential systemic effects.

Risk Factors

• Lack of vaccination or incomplete immunization against diphtheria.
• Close contact with an infected individual.
• Poor hygiene or crowded living conditions.
• Travel to regions with low vaccination coverage.
• Pre-existing skin injuries or breaks in the skin.

Symptoms

• Non-healing ulcers or lesions on the skin.
• Redness, swelling, or pain at the affected site.
• Yellowish or grayish membrane over the ulcer.
• Low-grade fever (in some cases).
• Swollen regional lymph nodes.

Diagnosis

Diagnosis involves clinical assessment of skin lesions, particularly the presence of a characteristic membrane. Laboratory tests, including culture of lesion swabs or PCR, confirm the presence of Corynebacterium diphtheriae. Toxin detection may also be performed to assess systemic risk.

Treatment Options

Treatment typically includes antitoxin therapy to neutralize circulating toxin and antibiotics (e.g., penicillin or erythromycin) to eliminate the bacteria. Wound care and hygiene measures are also important to prevent spread. Vaccination status should be reviewed and updated if needed.

Prognosis and Follow-Up

With prompt treatment, most cases of cutaneous diphtheria resolve without severe complications. Follow-up may include monitoring for signs of systemic involvement and ensuring completion of antibiotic therapy. Long-term complications are rare but can occur if toxin production is significant.

Complications

• Systemic spread of toxin leading to myocarditis or neuropathy.
• Secondary bacterial infections of the skin.
• Delayed wound healing.

Lifestyle & Prevention

• Maintain good skin hygiene and promptly clean any injuries.
• Ensure up-to-date vaccination against diphtheria.
• Avoid contact with individuals who have active skin lesions.
• Practice hand hygiene to reduce transmission risk.

When to Seek Professional Help

Seek medical attention if you develop non-healing skin ulcers, especially with a grayish membrane, or if you have been exposed to someone with confirmed cutaneous diphtheria. Prompt evaluation is important to prevent complications.

Tips for Medical Coders

Document the presence of characteristic skin lesions and any confirmed laboratory testing for Corynebacterium diphtheriae to support the diagnosis. Note vaccination status and any systemic symptoms, as these may impact coding and clinical management. Ensure the code A36.3 is used for cutaneous diphtheria without additional specificity unless documented.