A seven-month-old girl presented with a rash on her face that had worsened over the previous two days. The patient had a history of eczema and was given hydrocortisone and emollients in the emergency department one week earlier. The rash improved, but then rapidly worsened.
On physical examination, she was non-toxic but had a body temperature of 102.1°F (38.9°C). She was very fussy and scratched at her arms and body. Physical examination also revealed multiple small, elevated vesicles and papules on her face (Figure 1). Many of the vesicles were ruptured or umbilicated, and some coalesced to form crusted plaques. A cluster of vesicles and bullae were noted on her right hand (Figure 2), and scattered ruptured vesicles were noted on her chest and back.
The answer is B: eczema herpeticum. Eczema herpeticum is characterized by erythematous, ruptured, and crusting vesicles. The rash typically begins on the head or neck as dome-shaped vesicles that subsequently umbilicate, rupture, and often coalesce. The rash usually occurs on areas affected by atopic dermatitis, although it may also affect previously healthy skin.1 Eczema herpeticum is pruritic and may be accompanied by fever, malaise, lymphadenopathy, vomiting, and diarrhea. It is most common in children two to three years of age,2 although it may occur at any age.
Eczema herpeticum is caused by primary herpes simplex virus 1 infection in patients with a disrupted skin barrier from underlying atopic dermatitis.2 The diagnosis is clinical and is based on history of atopic dermatitis and rapid development of the characteristic rash. This can be confirmed using polymerase chain reaction testing, direct fluorescent antibody staining, or viral culture.3 Eczema herpeticum is often accompanied by a staphylococcal infection,1 although this is not the primary etiology.
Eczema herpeticum is a dermatologic emergency.1 To prevent further dissemination, acyclovir (Zovirax) therapy should be initiated when eczema herpeticum is suspected, and not delayed for laboratory confirmation.3 Additional treatment may include cool compresses; an emollient, such as petroleum jelly; antihistamines to decrease pruritus; and treatment of any bacterial superinfection.3 The condition has a mortality rate of up to 10 percent, even with treatment.2 Topical steroids should be avoided to prevent further insult to the skin's immune response.
The distribution of the contact dermatitis rash is related to the exposure. Erythema is the most common presentation, although vesicles or bullae may occur. Contact dermatitis is pruritic and may lead to visible excoriations. Widespread crusting is uncommon.1
Eczema vaccinatum is a rare cutaneous reaction to smallpox immunization (vaccinia virus). The condition is marked by development of umbilicated vesicles and papules, usually in a uniform stage of development. It occurs in persons with predisposing factors, such as a history of atopic dermatitis, after receiving the smallpox vaccine or after a close contact receives the vaccine.4
Impetigo is common in children and can occur anywhere on the body. The condition sometimes begins as a small vesicle or pustule, but rarely demonstrates widespread vesiculation. The crusting is typically honey-colored, rather than red or brown, and erythema usually is not present.1
Varicella typically begins on the trunk and spreads to the face and extremities. The classic lesion is a pink or red papule that develops into an overlying vesicle. The vesicle then ruptures and crusts. Multiple stages may appear simultaneously.1
|Contact dermatitis||Occurs in all age groups; distribution is related to exposure; primarily appears as erythema, but vesicles or bullae may occur; pruritic; widespread crusting is uncommon|
|Eczema herpeticum||Most common in children two to three years of age; begins on head or neck; dome-shaped vesicles that umbilicate, rupture, and often coalesce; caused by herpes simplex virus 1 infection|
|Eczema vaccinatum||Occurs on areas affected by atopic dermatitis after exposure to smallpox vaccine; umbilicated papules and vesicles usually in a uniform stage of development|
|Impetigo||Common in children; can occur anywhere on the body; may begin as a vesicle or pustule, but is rarely widespread; honey-colored crusting|
|Varicella||Begins on trunk then spreads to face and extremities; vesicle on a pink papule; multiple stages present simultaneously|