Common Childhood Rashes

Images of the various rashes may be available by clicking links. In some cases links are to factual information needed for recognition/management of a systemic disease with dermatological manifestations. The on-line dermatological atlas in the internet section will be useful to find any additional images.

Clear fluid

Consider:

• Varicella (chicken pox) - vesicles (initially papules, often not noticed), appearing as 'drops of water'. Superficial, thin-walled with surrounding erythema rapidly changing to pustules and crusts. Appears in crops with all stages represented. First appears on face and scalp then spreads to trunk and extremities. Crusts fall off in 1-3 weeks leaving pink base. Initial fever is classically high before becoming low grade. Beware of dyspnoea/cough which may indicate varicella zoster virus (VZV) pneumonitis.¹
• Herpes simplex virus infection (HSV) - eczema herpeticum (HSV infection superimposed on pre-existing, often mild, eczema causing an eruption of crusty vesicles and eczematous patches).²
• Impetigo - this usually takes the form of itchy lesions with macules, vesicles, bullae, pustules and gold-coloured crusts caused by Staphylococcus aureus or group A beta-haemolytic streptococci.² Staphylococcal scalded skin syndrome(appears as scalded skin, due to focal staphylococcal infection – eg phage type 71 – releasing an exotoxin).³
• Erythema multiforme, classically appearing as target lesions (erythematous ring with central bulla)²
• Stevens-Johnson syndrome⁴
• Toxic epidermal necrolysis⁴
• Pompholyx (on hands/feet)⁵

Pustular rashes

Consider:

• Acne vulgaris (there should be accompanying comedones)⁶
• Folliculitis (small pustules at base of hairs)⁷
• Pustular psoriasis²

Consider:

• Urticaria⁸
• Molluscum contagiosum (pearly or fleshy, umbilicated, ie central depression in papule)
• Scabies (itchy, excoriated, S-shaped burrows should be visible with magnifying glass)
• Insect bites
• Keratosis pilaris (keratin accumulation at base of hair follicles)⁹

With epidermal breakage (eczematous)?

Atopic eczema, typically involves itching erythematous patches, papules and plaques with moist crusted erosions on face neck and upper trunk, also elbows and knees.

Without epidermal breakage²

Consider:

• Seborrhoeic dermatitis
• Psoriasis
• Tinea corporis/capitis
• Pityriasis Rosea

Consider:

• Cellulitis¹⁰
• Kawasaki's disease¹¹
• Scarlet fever and the viral exanthemas e.g.:
  • Roseola infantum – (Sixth Disease)¹²
  • Primary human herpes viral (HHV6 & 7) infection. Most common age is under two years, frequent cause of infantile febrile seizures. Small blanchable pink macules and papules found on trunk and neck. Associated with high fever prior to defervescence & appearance of rash on fourth day. Often asymptomatic.¹³
  • Erythema infectiosum - (slapped cheek syndrome or fifth disease) caused by Parvovirus B19.^14,15
  • Measles - presents as erythematous macules and papules, initially discrete may become confluent on face, neck and shoulders.¹⁶ On mucous membranes, Koplik's spots (tiny bluish-white papules with erythematous areola) may develop. Also, upper respiratory tract infection with cough, malaise and fever subsiding as rash increases (measles prodrome = the 4 C's - cough, coryza, conjunctivitis and cranky++!)
  • Rubella (German measles) pink macules and papules starting on forehead and spreading to face, trunk and extremities on first day. Fades from face on second day and rest of body by third day. Petechiae on soft palate before rash. Low fever.
  • Scarlet fever (=scarlatina) exotoxin mediated rash (Group A Streptococcus) - sore throat then general erythema (classically with perioral sparing), followed by confluent petechiae in skin folds (Pastia sign) due to increased capillary fragility. Strawberry tongue (initially white, then red). Skin desquamation (peeling) frequently follows rash.¹⁷

Consider:

• Meningococcal meningitis (not common but should be excluded) Early, in 75% cases 2-10mm macular or maculopapular rash that blanches on pressure becomes apparent within first 24 hours of disease; sparsely distributed on face, trunk and lower extremities.¹⁸ Use 'glass test' to assess 'blanchability' of rash by placing glass tumbler against lesions and applying pressure. Later the petechiae in centre of macules become haemorrhagic.
• Henoch-Schonlein purpura¹⁹
• Idiopathic thrombocytopaenic purpura (ITP), leukaemia and other haematological disorders²⁰
• Trauma, non-accidental Injury
• Enterovirus infections²¹
• Miscellaneous conditions:
  • Warts²
  • Verrucas
  • Head lice⁷

Summary of Paediatric Skin Rashes: Adapted from Paediatric Handbook 6th Ed. Royal Children's Hospital, Melbourne.

The full list of the original exanthems is:

• First disease = Measles or rubeola
• Second disease = Scarlet fever
• Third disease = Rubella or German measles
• Fourth disease = Filatov or Dukes disease
• Fifth disease = Erythema infectiosum (slapped cheek syndrome)
• Sixth disease = Exanthem subitum or roseola infantum

This ordinal nomenclature came about because at the turn of the century there were classically three exanthematous diseases recognised: measles, rubella, and scarlet fever. Then, in 1900, Dr. Clement Dukes, medical officer at Rugby School described another exanthem which he called "fourth disease". In 1905 erythema infectiosum (a term already in use for 6 years applying to the disease described previously by Tshamer and later by Escherich) was the fifth disease added to the list. Later sixth disease (roseola infantum) was recognised, and fourth disease was rejected by most observers because of insufficient evidence to support its existence as an independent entity. So now first, second, third and sixth diseases are now referred to by their more common names, leaving fifth disease as a solitary reminder of the days when, unaided by sophisticated microbiology, observant clinician-epidemiologists were able to categorize a group of confusing exanthems.