Dr. Sheila Fallon-Friedlander
A major aggravating factor associated with atopic dermatitis is the presence of microorganisms on the patient’s skin surface. S aureus and Streptococcus pyogenes can exacerbate chronic skin inflammation. S aureus can colonize the skin or the respiratory tract in healthy patients and become pathogenic under conditions such as skin barrier breakdown and diminished immunity. Atopic dermatitis patients are highly susceptible to staphylococcal skin infections. Studies have shown that between 80% and 100% of patients with atopic dermatitis have nasal or skin colonization by S aureus vs 5% to 30% in individuals without atopic dermatitis. First and second generation cephalosporins are suitable for treatment of patients infected with methicillin-susceptible S aureus and MRSA is best treated with clindamycin and trimethoprim/sulfamethoxazole. Antimicrobial therapy should be tailored on the basis of local resistance patterns. Streptococcal infections may be treated with clindamycin and cephalexin.
Eczema herpeticum, also known as a form of Kaposi varicelliform eruption caused by viral infection, usually with the herpes simplex virus (HSV), is an extensive cutaneous vesicular eruption that arises from pre-existing skin disease, usually atopic dermatitis. Children with atopic dermatitis have a higher risk of developing eczema herpeticum, in which HSV type 1 is the most common pathogen. Patients with this condition may be treated with acyclovir.
Eczema cocksackium may also occur in patients with atopic dermatitis. In one case series, 51% of patients diagnosed with Eczema cocksackium had a history of atopic dermatitis. This enterovirus-associated exanthem is characterized by fever, stomatitis of the oral mucosa, and a vesicular rash affecting the hands, feet, and occasionally the buttocks. About one-third of infants <1 year of age may also present with bullae. Symptoms are strikingly similar to eczema herpeticum caused by HSV type 1. Patients with eczema cocksackium have been successfully treated with wet wrap therapy and low-dose corticosteroids. Bleach baths are also effective for both killing of pathogens and decreasing inflammation.