Infectious rashes in childhood

This article covers various infectious exanthems (rashes) in childhood, including measles, scarlet fever, rubella, fifth disease, roseola infantum, chickenpox, and hand, foot, and mouth disease.

For more information on each specific condition, see the respective articles.

Overview of infectious rashes in childhood
	Pathogen	Appearance of exanthem		Course of exanthem	Other clinical features
Measles	Measles virus	Erythematous, maculopapular (spots are ∼ 1–10 mm in size) Blanching Partially confluent		Begins on the face, frequently behind the ears Disseminates to the rest of the body Fades after ∼ 5 days with brown discoloration and desquamation	Prodromal stage Coryza, cough, and conjunctivitis Koplik spots Exanthem stage High fever, malaise Generalized lymphadenopathy
Scarlet fever	Streptococcus pyogenes	Fine, erythematous, maculopapular (sandpaper-like texture) Blanching Pastia lines (linear petechiae in the groin, armpit, and elbow creases)		Begins in the neck region Disseminates to the head, trunk, and extremities Brown discoloration and desquamation of the skin during the second to fourth week of infection	High fever with sudden onset Strawberry tongue Tonsillopharyngitis
Rubella	Rubella virus	Fine, erythematous maculopapular rash (spots ∼ 2–3 mm in size) Blanching Nonconfluent medium-sized spots		Begins behind the ears Extends to the trunk and extremities Symptoms usually disappear within 3 days	Good general condition, mild fever Suboccipital and post-auricular lymphadenopathy Forchheimer sign
Fifth disease (erythema infectiosum)	Parvovirus B19	Maculopapular Initially confluent Lace-like and reticular appearance over time Becomes more pronounced after exposure to sunlight or heat		Slapped cheek appearance: flushed cheeks with perioral pallor Can spread to extremities and trunk Fades after ∼ 5–8 days May be recurrent for several months following the initial infection	Good general condition Arthritis
Roseola infantum (exanthem subitum)	Human herpesvirus 6	Erythematous, maculopapular (spots ∼ 2–5 mm in size) Patchy, blanching		Develops as the fever subsides Originates on the trunk and may spread to the face and extremities Frequently observed from only several hours to a maximum of 3 days	Good general condition Initial sudden high fever for 3–5 days (three-day fever) Nagayama spots
Chickenpox (varicella)	Varicella-zoster virus	Vesicular rash on erythematous background Starry sky: simultaneous occurrence of various stages of rash (e.g., vesicles, crusted papules)		Begins on trunk, scalp, face, and proximal limbs Involves hands, feet, and mucous membranes Severe pruritus Fades after ∼ 1 week	Prodrome possible (1–2 days prior to exanthem onset) Oropharyngeal and urogenital ulcers
Hand, foot, and mouth disease	Coxsackie A virus	Tender macules Vesicular rash		Affects feet and hands Rarely generalizes Fades after ∼ 4 days	Poor general condition Highly contagious Stomatitis and enanthem Fever

Drug reactions should always be considered as a potential cause of a rash.