Facial Ulcers and Blisters
Differential Diagnosis
Common Diagnoses
- Impetigo
- Herpes Simplex Virus (HSV)
- Herpes Zoster
- Basal Cell Carcinoma (BCC)
- Keratoacanthoma
Occasional Diagnoses
- Squamous Cell Carcinoma (SCC)
- Ulcerating Malignant Melanoma and Lentigo Maligna (Hutchinson’s Freckle)
- Drugs (e.g. Barbiturates)
- Acne Excoriée
- Ulcerating Dental Sinus
Rare Diagnoses
- Dermatitis Artefacta
- Tuberculosis
- Pemphigus
- Actinomyces
- Primary Syphilitic Chancre or Tertiary Syphilitic Gumma
- Cutaneous Leishmaniasis
- Cancrum Oris
Ready Reckoner
Key distinguishing features of the most common diagnoses
| BCC | Herpes Zoster | Keratoacanthoma | Impetigo | HSV | |
|---|---|---|---|---|---|
| Feverish and Unwell | No | Yes | No | No | Possible |
| Rapid Development | No | Yes | Yes | Yes | Yes |
| Recurrent | Possible | No | No | Possible | Yes |
| Occurs in Children | No | Possible | No | Yes | Yes |
| Multiple Lesions | No | Yes | No | Yes | Yes |
Possible Investigations
- Acute lesions very rarely require investigation; chronic lesions pose more of a diagnostic problem. In such cases, biopsy, or excision biopsy, is the gold standard test. Cytology after scraping the lesion with a scalpel blade may be helpful in diagnosing basal cell carcinoma. Syphilis serology may very rarely be useful if primary or tertiary syphilis is suspected.
Top Tips
- Remember that herpes simplex can occur on the face at sites other than the lip. The appearance of the lesions and their recurrent nature should provide the diagnosis.
- ‘Rodent ulcer’ is a kinder term than basal cell carcinoma, especially for small lesions, as it is less likely to arouse unnecessary anxiety. Nonetheless, impress upon the patient the importance of attending the appointment with the specialist.
- Patients with herpes zoster are at risk of a number of anxieties because of the existence of various ‘old wives’ tales’ about shingles. Establish any fears and take time to explain the natural history of the condition, including the possibility of post-herpetic neuralgia.
- In children with recurrent impetigo, consider an underlying condition – particularly eczema.
Red Flags
- If in any doubt about the diagnosis, urgent dermatological referral for skin biopsy is indicated. Remember that chronic facial ulceration is rarely benign.
- Ulceration in a previously abnormally pigmented area of skin suggests advanced local malignancy.
- Beware attempting excision biopsy of facial lesions unless specially trained. Areas of cosmetic importance can be medico-legal minefields.
- Ask about foreign travel – leishmaniasis develops from the bite of a Mediterranean or South American sandfly.
- Beware of herpes zoster or simplex developing around the eye – significant complications may follow, so treat and follow up carefully and obtain an ophthalmological opinion if necessary.