What are the causes of strawberry tongue?

Causes of Strawberry Tongue

Strawberry tongue is most commonly caused by Kawasaki disease, scarlet fever (Group A Streptococcal infection), toxic shock syndrome, and multisystem inflammatory syndrome in children (MIS-C). 1, 2, 3

Primary Infectious Causes

Scarlet Fever (Group A Streptococcal Infection)

• Presents with a characteristic "strawberry tongue" that is initially white-coated, then becomes bright red with prominent fungiform papillae 1, 2, 3
• Accompanied by fever, sore throat, and a characteristic sandpaper-like rash 1
• More common in children aged 5-15 years 2
• The strawberry tongue appearance is indistinguishable from that seen in Kawasaki disease 1

Toxic Shock Syndrome (TSS)

• TSST-1-mediated exanthematous disease can present with strawberry tongue 4
• Shows chronological changes in tongue appearance over the disease course 4
• Associated with systemic toxicity and multiorgan involvement 4

Primary Vasculitic/Inflammatory Causes

Kawasaki Disease

• The most critical diagnosis to consider, as untreated disease leads to coronary artery aneurysms in up to 20% of cases 1, 5
• Strawberry tongue appears with erythema and prominent fungiform papillae, identical to scarlet fever 1
• Associated oral findings include erythema, dryness, fissuring, peeling, cracking, and bleeding of the lips, plus diffuse erythema of oropharyngeal mucosae 1
• Oral ulcerations and pharyngeal exudates are NOT seen—their presence suggests an alternative diagnosis 1
• Predominantly affects children under 5 years of age, though can occur in adolescents 5, 6, 7
• Diagnosis requires fever for at least 5 days plus at least 4 of 5 principal features: extremity changes, polymorphous exanthem, bilateral conjunctival injection, oral/lip changes including strawberry tongue, and cervical lymphadenopathy 1
• Incidence rates in Asians are up to 20 times higher than Caucasians 6

Multisystem Inflammatory Syndrome in Children (MIS-C)

• Occurs 2-6 weeks after SARS-CoV-2 infection 1, 8
• Can present with Kawasaki disease-like features including strawberry tongue, red/cracked lips, conjunctival injection, rash, and cervical lymphadenopathy 1
• Younger children with MIS-C are more likely to present with KD-like features including strawberry tongue 1
• Increased incidence in patients of African, Afro-Caribbean, and Hispanic descent 1
• Distinguished from classic KD by more prominent gastrointestinal and neurologic symptoms, higher frequency of shock, and cardiac dysfunction 1

Post-Infectious Inflammatory Conditions

Candidiasis (Oral Thrush)

• Can cause a bright red tongue, especially after white plaques are removed 2, 3
• More common in immunocompromised patients 2, 3
• Diagnosed by scraping and microscopic examination with KOH preparation 2, 3

Systemic Conditions

Vasculitis (Non-Kawasaki)

• Can present with bright red tongue as part of multiorgan involvement 2, 3
• Associated with conditions like sarcoidosis 2

Thyroid Disorders

• Hyperthyroidism can cause tongue erythema 2, 3
• Associated with other symptoms of thyroid dysfunction 2

Other Inflammatory Conditions

Burning Mouth Syndrome

• Presents with bright red tongue and burning sensation 2, 3
• Predominantly affects peri- and post-menopausal women 2, 3
• Often accompanied by dry mouth, abnormal taste, and depression 2

Critical Diagnostic Pitfalls

The key clinical challenge is distinguishing between Kawasaki disease, MIS-C, and scarlet fever, as they share overlapping features but require different management approaches. 1

• Kawasaki disease requires diagnosis within the first 10 days to prevent coronary complications with IVIG and aspirin therapy 1, 5
• MIS-C requires multidisciplinary evaluation including cardiology assessment, as patients can develop coronary artery aneurysms even without classic KD features 1
• The absence of pharyngeal exudate favors Kawasaki disease or MIS-C over scarlet fever 1
• Clinical features in Kawasaki disease appear sequentially and may not all be present simultaneously, making diagnosis challenging 5
• Blood cultures and rapid strep testing help differentiate bacterial causes from vasculitic conditions 1