History

Fact Explanation
Clusters of itchy and/or painful blisters in areas of pre-existing skin disease. Found mostly on face and neck, they may be red/purple or black in colour. Disseminated, distinctly monomorphic eruption of dome-shaped vesicles which may transform into pustules or erosions are typical findings with eczema herpeticum. [2] They may lead to hemorrhage; this is the reason for its red/purple or black colour. These lesions are caused by HSV1, HSV2 or rarely coxsackie A 16 or vaccinia virus. Disruption of epidermal barrier and immunosuppression are risk factors. [3]
Flu-like symptoms including fever, malaise and chills [1] Normal response of the body to infection.
History of pre-existing dermatoses such as atopic dermatitis, psoriasis, eczema, irritant contact dermatitis, seborrheic dermatitis, pemphigus vulgaris, bullous pemphigoid, mycosis fungoides, ichthyosis vulgaris, Darier's disease, cutaneous T-cell lymphoma, Wiskott-Aldrich syndrome and thermal burns etc. [1,2,3] Skin is at high risk of infection by viruses and bacteria owing to the disruption of epidermal barrier function(2). Patients with some features of atopic dermatitis such as early onset atopic dermatitis, head and neck atopic dermatitis, or large body surface area involvement have a higher risk of eczema herpeticum. [1]
Photophobia, blurred vision, redness and tearing of the eye and sometimes but not always blisters around the eye/eye lid. If viral infection has spread to the eye causing herpetic keratitis. This is an ophthalmological emergency. [3]
Previous history of eczema herpeticum or other HSV infection. Because recurrence could occur with eczema herpeticum. Viral infection is believed to occur as a result of auto-inoculation in a host with latent infection or may also be from contact with an infected individual. [2]
References
  1. 1. OLSON J, ROBLES DT, KIRBY P, COLVEN R. Kaposi varicelliform eruption (eczema herpeticum). Dermatol Online J [online] 2008 Feb 28, 14(2):18 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18700121
  2. 2. LIAW FY, HUANG CF, HSUEH JT, CHIANG CP. Eczema herpeticum: a medical emergency. Can Fam Physician [online] 2012 Dec, 58(12):1358-61 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23242894
  3. 3. POPOV Y, NIKOLOV R, LALOVA A. Localized eczema herpeticum with unilateral ocular involvement. Acta Dermatovenerol Alp Pannonica Adriat [online] 2010 Oct, 19(3):35-7 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20976420

Examination

Fact Explanation
Typical rash The skin might begin with erythematous changes presenting as small, monomorphic papulovesicles that are domed shaped. They may rupture to form small punched out ulcers overlying an erythematous base. They may coalesce to form denuded areas that are prone to secondary bacterial colonization. Most often found on the face, neck and upper trunk. [1,2,4]
Fever HSV stimulate phagocytes to produce endogenous pyrogens such as IL-1 , IL-6 , TNF alpha and they cause an elevation in the "set point" for normal body temperature., in the hypothalamus. The body temperature rises until it reaches the set point by shivering, piloerection and vasoconstriction resulting in fever. [5]
Lymphadenopathy HSV enters lymphatic vessels and gets filtered through lymph nodes. Cells within lymph nodes proliferate in response to antigenic stimuli by the virus which causes lymph nodes to enlarge. [6]
References
  1. 4. LEUNG DY. Why is eczema herpeticum unexpectedly rare? Antiviral Res [online] 2013 May, 98(2):153-7 [viewed 22 June 2014] Available from: doi:10.1016/j.antiviral.2013.02.010
  2. 1. OLSON J, ROBLES DT, KIRBY P, COLVEN R. Kaposi varicelliform eruption (eczema herpeticum). Dermatol Online J [online] 2008 Feb 28, 14(2):18 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18700121
  3. 5. BERNHEIM HA, BLOCK LH, ATKINS E. Fever: pathogenesis, pathophysiology, and purpose. Ann Intern Med [online] 1979 Aug, 91(2):261-70 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/223485
  4. 6. DOUKETIS JD. Lymphadenopathy, The Merck Manual for health care professionals 2012 sep (viewed 13 June 2014) Available from: http://www.merckmanuals.com/professional/cardiovascular_disorders/lymphatic_disorders/lymphadenopathy.html
  5. 2. LIAW FY, HUANG CF, HSUEH JT, CHIANG CP. Eczema herpeticum: a medical emergency. Can Fam Physician [online] 2012 Dec, 58(12):1358-61 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23242894

Differential Diagnoses

Fact Explanation
Eczema vaccinatum Important differential to exclude as it can be fatal if it leads to supra-epiglottic edema. Lesions might be distant from the place of inoculation. Papules, vesicles, umbilicated pustules or erosions are typical. Note that a patient may have recent history of receiving smallpox vaccination or of being in contact with someone who received the vaccine recently. [2]
Impetigo These lesions commonly caused by staphylococcus aureus begin as a single red papule or macule that quickly progress to a vesicle and an erosion when contents are dried, they form honey coloured crusts. They have fewer systemic symptoms. Infection commonly resolves spontaneously. Note there could be eczema herpeticum with bacterial superinfection like impetigo; underlying viral infection may go misdiagnosed in these cases. Suspect eczema herpeticum when patient is presented with fever and characteristic rash. [7]
Varicella Zoster Disseminated pruritic macules that progress to form clear fluid filled vesicles (like dew drops on a rose petal) caused by varicella zoster virus. Consider if recent history of contact with infected individual with chicken pox. [2]
References
  1. 2. LIAW FY, HUANG CF, HSUEH JT, CHIANG CP. Eczema herpeticum: a medical emergency. Can Fam Physician [online] 2012 Dec, 58(12):1358-61 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23242894
  2. 7. COLE C, GAZEWOOD J. Diagnosis and treatment of impetigo. Am Fam Physician [online] 2007 Mar 15, 75(6):859-64 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17390597

Investigations - for Diagnosis

Fact Explanation
Diagnosis is mainly clinical Due to its characteristic appearance occurring together with fever. [1]
Tznack test An easy and quick bedside test. Multinucleated giant cells with acantholytic balloon cells confirm a virus infection but not virus specific. Provides a rapid diagnosis. [1,2]
Direct florescent antibody testing A fluorescently tagged antibody can detect an HSV antigen and distinguished between HSV-1 and HSV-2 infections. Results are available in a few hours. [2]
Viral culture Culture taken from a fresh vesicle is sensitive or specific for HSV infection, but takes at least 48 hours but if culture is taken from crust, it will be negative. [1,2
Bacterial culture Due to risk of co-existent bacterial infection [1]
Refer for ophthalmological tests To evaluate ophthalmological involvement by the virus.
References
  1. 1. OLSON J, ROBLES DT, KIRBY P, COLVEN R. Kaposi varicelliform eruption (eczema herpeticum). Dermatol Online J [online] 2008 Feb 28, 14(2):18 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18700121
  2. 2. LIAW FY, HUANG CF, HSUEH JT, CHIANG CP. Eczema herpeticum: a medical emergency. Can Fam Physician [online] 2012 Dec, 58(12):1358-61 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23242894

Management - General Measures

Fact Explanation
Analgesia Analgesics such as acetaminophen or NSAIDs such as Ibuprofen could be given for pain relief.
Patient education Patients, especially atopic and immunocompromised individuals should be educated on risk factors, typical features and regarding its recurrence to avoid complications and mortality.
References

Management - Specific Treatments

Fact Explanation
Aciclovir/ valacyclovir (IV/Oral administration) Nucleoside analog antiviral agents. They inhibit viral DNA polymerase. Note that their use should not be delayed pending on laboratory tests as it may lead to keratoconjunctivitis with possible stromal scarring and ultimately blindness and as well as viremia and death by multi-organ involvement including meningitis, encephalitis, herpes hepatitis and disseminated intravascular coagulation. [1,4] If the disease is severe and for immunocompromised patients, give IV drugs. If less severe disease oral treatment is sufficient. if the infection is chronic and recurrent, acyclovir or valacyclovir should be given as prophylaxis. [3,10] Pyrophosphate analog foscarnet have shown some efficacy in treating acyclovir-resistant immunocompromised patients with HSV infection, although its toxicities such as nephrotoxicity and induction of electrolyte disorders limit its use. [9,10]
Antibiotic therapy If bacteria are found in culture,these should be initiated. eg: staphylococcus aureus( Cephalexin , clindamycin , doxycycline or trimethoprim-sulphamethoxazole). [2]
Topical antibiotic cream like silver sulphadiazine. Given when there's no bacterial infection but for prophylaxis against a possible secondary infection. [1]
Ophthalmic acyclovir Given if skin around eye is involved to treat ophthalmologic complications. [4]
References
  1. 1. OLSON J, ROBLES DT, KIRBY P, COLVEN R. Kaposi varicelliform eruption (eczema herpeticum). Dermatol Online J [online] 2008 Feb 28, 14(2):18 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/18700121
  2. 2. LIAW FY, HUANG CF, HSUEH JT, CHIANG CP. Eczema herpeticum: a medical emergency. Can Fam Physician [online] 2012 Dec, 58(12):1358-61 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/23242894
  3. 4. LEUNG DY. Why is eczema herpeticum unexpectedly rare? Antiviral Res [online] 2013 May, 98(2):153-7 [viewed 22 June 2014] Available from: doi:10.1016/j.antiviral.2013.02.010
  4. 8. NATH AK, SORI T, THAPPA DM. A case series of kaposi's varicelliform eruption in dermatology in-patients in a tertiary care centre. Indian J Dermatol [online] 2011 Jan, 56(1):110-5 [viewed 22 June 2014] Available from: doi:10.4103/0019-5154.77572
  5. 9. WAGSTAFF AJ, BRYSON HM. Foscarnet. A reappraisal of its antiviral activity, pharmacokinetic properties and therapeutic use in immunocompromised patients with viral infections. Drugs [online] 1994 Aug, 48(2):199-226 [viewed 22 June 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/7527325
  6. 10. PIRET J, BOIVIN G. Resistance of herpes simplex viruses to nucleoside analogues: mechanisms, prevalence, and management. Antimicrob Agents Chemother [online] 2011 Feb, 55(2):459-72 [viewed 22 June 2014] Available from: doi:10.1128/AAC.00615-10