Kawasaki disease

Kawasaki · KD · mucocutaneous lymph node syndrome · incomplete Kawasaki

Persistent fever in a young child with red eyes, red mouth and a rash - the diagnosis to make before day 10, because treatment prevents coronary aneurysms.

ADMITBand B

Red flags

Fever of five days or more in any child without a clear source - think of this diagnosis explicitly and document that you did. Incidence peaks under 5, but Kawasaki disease occurs in older children and adolescents, in whom the diagnosis is more often delayed
Incomplete Kawasaki disease is common in infants under 1, who present with fewer features and have the highest aneurysm risk - a prolonged unexplained fever in an infant needs specialist discussion even with almost no rash
Any shock or haemodynamic instability - Kawasaki disease shock syndrome exists and is easily mistaken for sepsis
Presentation at or beyond day 10 - urgent, because the treatment window for preventing coronary damage is closing
Peeling of the fingers and toes in a child with a recent prolonged fever - a retrospective clue that must trigger review, not reassurance

Recognise

On light skin

Bright red non-vesicular polymorphous rash, cracked red lips, strawberry tongue, bilateral non-purulent conjunctival injection, and red swollen hands and feet with later peeling.

On brown and black skin

The rash and the palmar erythema are much harder to appreciate in brown and black skin, and the conjunctival injection and lip changes carry more of the diagnostic weight as a result - both are readily visible whatever the skin tone, because they are mucosal. Look at the eyes and the mouth first. Swelling and induration of the hands and feet can be felt even where redness cannot be seen, and the later periungual and perineal desquamation is tone-independent. A child of any ethnicity can have Kawasaki disease, and incidence is in fact highest in children of east Asian ancestry, so a rash that looks unimpressive must not lower your suspicion.

In any skin tone

Fever persisting five days or more is the entry point - and the fever is typically high and unresponsive to antipyretics
Bilateral non-purulent conjunctival injection, usually sparing the limbus
Mucosal change: cracked red lips, strawberry tongue, diffuse oral erythema
Changes in the extremities: swelling, erythema, then periungual peeling in the second week
Polymorphous rash - it has no single characteristic appearance
Cervical lymphadenopathy, usually unilateral and over 1.5 cm - the least often present of the principal features
An extremely irritable child, out of proportion to how they look

Distribution

Polymorphous rash over the trunk and limbs, often accentuated in the groin, with erythema and later desquamation of the hands and feet and perineal peeling.

Photographs

Bilateral conjunctival injection in Kawasaki disease. Both eyes are red, there is no pus and no stickiness - this is a non-exudative conjunc — Bilateral conjunctival injection in Kawasaki disease. Both eyes are red, there is **no pus and no stickiness** - this is a non-exudative conjunctivitis, which is the point - and there is a pale ring of spared conjunctiva immediately around the iris, the perilimbal sparing. A red eye with discharge points away from Kawasaki; a red eye without it, in a child with prolonged fever, points towards it.
Fitzpatrick IV (Fitzpatrick type estimated from the photograph, not stated by the source) · Kim DS, Yonsei Medical Journal · Kim DS. Kawasaki disease. Yonsei Med J 2006;47(6):759-772, Figure 1 panel A (file via Wikimedia Commons) · CC BY-NC 3.0

Mouth signs in Kawasaki disease: a strawberry tongue with prominent papillae, and lips that are deep red, dry and vertically cracked. There — Mouth signs in Kawasaki disease: a **strawberry tongue** with prominent papillae, and lips that are deep red, dry and vertically cracked. There is no ulceration and no exudate - mouth ulcers argue against the diagnosis. These mucosal changes show whatever the skin tone, which makes them a more reliable part of the criteria than the polymorphous rash in a child with brown or black skin.
Fitzpatrick IV (Fitzpatrick type estimated from the photograph, not stated by the source) · Kim DS, Yonsei Medical Journal · Kim DS. Kawasaki disease. Yonsei Med J 2006;47(6):759-772, Figure 1 panel B (file via Wikimedia Commons) · CC BY-NC 3.0

Erythema of both palms in the acute phase, usually with firm, painful swelling of the backs of the hands. Palms and soles are the one place — Erythema of both palms in the acute phase, usually with firm, painful swelling of the backs of the hands. **Palms and soles are the one place erythema stays visible on darker skin**, because they are far less pigmented than the rest of the body, so examine the hands and feet of any child you are considering Kawasaki in. The child is often miserable and will not use the hands.
Fitzpatrick IV (Fitzpatrick type estimated from the photograph, not stated by the source) · Kim DS, Yonsei Medical Journal · Kim DS. Kawasaki disease. Yonsei Med J 2006;47(6):759-772, Figure 1 panel D (file via Wikimedia Commons) · CC BY-NC 3.0

Peeling of the fingers in the subacute phase. Sheets of skin lift from the fingertips and the edges of the nails first and work backwards, t — Peeling of the fingers in the subacute phase. Sheets of skin lift **from the fingertips and the edges of the nails first** and work backwards, typically in the second or third week. This is a late sign: by the time you see it the window for immunoglobulin has usually closed, so it is most useful retrospectively, in a child who had an unexplained prolonged fever a fortnight ago and now needs an echocardiogram rather than treatment.
Fitzpatrick IV (Fitzpatrick type estimated from the photograph, not stated by the source) · Kim DS, Yonsei Medical Journal · Kim DS. Kawasaki disease. Yonsei Med J 2006;47(6):759-772, Figure 1 panel F (file via Wikimedia Commons) · CC BY-NC 3.0

Redness and induration at the site of an earlier BCG vaccination - small crusted papules on an inflamed plaque over the deltoid. This is clo — Redness and induration at the site of an earlier BCG vaccination - small crusted papules on an inflamed plaque over the deltoid. **This is close to specific for Kawasaki disease** and is easy to miss because nobody looks at an old vaccination scar. It is most useful in infants, who are also the group most likely to present incompletely and most at risk of coronary aneurysms. Worth a deliberate look in any BCG-vaccinated child with prolonged fever.
Fitzpatrick IV (Fitzpatrick type estimated from the photograph, not stated by the source) · Kim DS, Yonsei Medical Journal · Kim DS. Kawasaki disease. Yonsei Med J 2006;47(6):759-772, Figure 1 panel G (file via Wikimedia Commons) · CC BY-NC 3.0

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Scarlet fever — Both give strawberry tongue, rash and desquamation; scarlet fever has a sandpaper rash, responds to penicillin and lacks conjunctival injection
Measles — Both give fever, rash and red eyes; measles has coryza, cough and Koplik spots, and the child is miserable with a descending rash
Toxic shock syndrome — Both give fever, diffuse erythema, mucosal change and later desquamation; TSS is shocked from the outset
DRESS - drug reaction with eosinophilia and systemic symptoms — Both give prolonged fever with a widespread eruption; DRESS follows a drug by weeks and has eosinophilia

What to do in the ED

Count the fever days explicitly and record the number - the diagnosis is built on duration
Examine the eyes, the mouth, the hands and feet, and the groin deliberately, and document each principal feature as present or absent
Take FBC, CRP, ESR, liver function, albumin and urinalysis - sterile pyuria and a raised inflammatory response support the diagnosis
Discuss with paediatrics the same day. Do not discharge a child with five days of unexplained fever on the basis that the rash is unimpressive
Where the picture is incomplete, the AHA statement sets out a specific laboratory and echocardiographic algorithm - read it at the source rather than reconstructing the thresholds from memory. Note two published errata (Circulation 2025;151(8):e677-e679 and 2025;151(13):e863): check them before quoting any threshold. The limbal sparing, the 1.5 cm nodal threshold and the incomplete-disease statement below are the conventional AHA criteria, but we have only been able to read the statement's abstract - treat them as a prompt to examine and to discuss, not as reproduced guideline text
Echocardiography and immunoglobulin are specialist decisions, but the ED decision is simply whether this child is discussed today
Warn against giving ibuprofen routinely if aspirin is started; analgesic choices are for the treating team

Disposition

ADMIT

Same-day paediatric assessment for any child with five or more days of unexplained fever and any principal feature; admit for treatment where the diagnosis is made. Untreated, coronary artery dilation or aneurysm develops in about 25% of patients, which is what makes this a time-critical diagnosis.

Sources

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