# Oral Manifestations of Systemic Disease

> Oral manifestations of systemic disease for NEET-PG Medicine, covering Koplik spots, Peutz-Jeghers pigmentation, aphthae, leukoplakia and gingival hyperplasia.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/oral-manifestations-of-systemic-disease
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Shafer's Textbook of Oral Pathology; Harrison's Principles of Internal Medicine
- How to cite: "Oral Manifestations of Systemic Disease", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/oral-manifestations-of-systemic-disease

## Direct answer

Oral manifestations of systemic disease are mucosal and dental signs that often reveal an underlying illness before other features appear. Koplik spots in measles, Peutz-Jeghers pigmentation, recurrent aphthae in Behçet disease and gingival hyperplasia from drugs such as phenytoin are classic examples. Recognising these signs can provide the first clue to a diagnosis that would otherwise be missed.

## What you must remember

- **Koplik spots:** small white spots on a red base over the buccal mucosa opposite the lower molars, appearing before the rash in measles.
- **Peutz-Jeghers pigmentation:** brown macules on the lips and buccal mucosa, associated with hamartomatous gastrointestinal polyps.
- **Aphthous ulcers:** recurrent painful ulcers linked with Behçet disease, inflammatory bowel disease, coeliac disease and HIV.
- **Leukoplakia:** a white plaque that cannot be wiped off; it is premalignant and linked with tobacco and areca nut use.
- **Drug-induced gingival hyperplasia:** caused by phenytoin, nifedipine and ciclosporin, and worsened by plaque.
- **Oral hairy leukoplakia:** white corrugated patches on the lateral tongue, linked with Epstein-Barr virus in HIV infection.
- **Strawberry tongue:** bright red, swollen papillae seen in Kawasaki disease and scarlet fever.
- **Mucosal pigmentation:** diffuse brown pigmentation of the buccal mucosa and gums in primary adrenal insufficiency.

## Reading the mouth as a diagnostic clue

Oral signs often appear before the systemic diagnosis is made, and the table lists the clues most often tested. Each row pairs a visible mucosal or dental finding with the condition it points toward.

| Oral sign | Systemic link | Key feature to note |
|---|---|---|
| Koplik spots | Measles | White specks on a red buccal base opposite the lower molars |
| Peutz-Jeghers pigmentation | Peutz-Jeghers syndrome | Brown macules on lips and buccal mucosa with intestinal polyps |
| Aphthous ulcers | Behçet disease, bowel disease, coeliac disease | Painful ulcers; in Behçet, genital ulcers and uveitis |
| Gingival hyperplasia | Phenytoin, nifedipine, ciclosporin | Enlarged gums worsened by plaque |
| Strawberry tongue | Kawasaki disease, scarlet fever | Bright red, swollen papillae |
| Mucosal pigmentation | Primary adrenal insufficiency | Diffuse brown colour of the buccal mucosa and gums |

Most of these signs are not diagnostic on their own, so they are read together with the drug history, fever pattern and family history. Gingival hyperplasia is the classic drug effect, and it improves when the drug is changed where clinically possible and plaque is controlled.

## Clues that get misread

Most errors come from confusing an oral sign with a more common benign lesion.

- **Trap:** wiping a white patch and calling it candidiasis when it persists — **Correct:** candidiasis scrapes off, whereas leukoplakia does not and needs biopsy because it is premalignant.
- **Trap:** attributing Koplik spots to chickenpox — **Correct:** Koplik spots are specific to measles and appear before the rash, whereas chickenpox produces vesicles.
- **Trap:** dismissing phenytoin gingival overgrowth as a dental problem — **Correct:** it is a drug effect worsened by plaque, so the fix is oral hygiene and review of the drug.
- **Trap:** calling recurrent aphthae Behçet disease — **Correct:** Behçet disease needs recurrent oral ulcers plus at least two of genital ulcers, eye disease, skin lesions or a positive pathergy test, and recurrent aphthae alone do not make the diagnosis.

## Frequently asked questions

### Which oral sign of measles appears before the rash?

Koplik spots are small white spots on a red base over the buccal mucosa opposite the lower molars. They appear before the rash of measles and are regarded as characteristic of the disease. Their presence in a febrile child with cough, coryza and conjunctivitis supports the diagnosis.

### Which drugs cause gingival hyperplasia?

Phenytoin, nifedipine and ciclosporin are the classic drugs that cause gingival hyperplasia. Plaque accumulation worsens the overgrowth, so oral hygiene is essential. Changing the drug where clinically possible usually improves the gums.

### Why is leukoplakia considered premalignant?

Leukoplakia is a white plaque that cannot be wiped off, and it carries a risk of progression to squamous cell carcinoma, particularly with tobacco or areca nut use. Biopsy is performed to exclude dysplasia or carcinoma. Erythroplakia, a red lesion, carries a higher malignant risk than leukoplakia.

### Which systemic diseases cause strawberry tongue?

Strawberry tongue is seen in Kawasaki disease and scarlet fever, with bright red, swollen papillae on the tongue. It appears alongside fever and rash in these conditions. Recognising it supports the clinical diagnosis in children.