P. Modiano et al., ACYCLOVIR-RESISTANT CHRONIC CUTANEOUS HERPES-SIMPLEX IN WISKOTT-ALDRICH SYNDROME, British journal of dermatology, 133(3), 1995, pp. 475-478
A 28-year-old man with Wiskott-Aldrich syndrome presented with ulcerat
ive-proliferative lesions on his face from which herpes simplex type 1
(HSV-1) was isolated. He was initially treated with 10 mg/kg of acycl
ovir (Zovirax(R)) intravenously every 8 h, but his skin lesions worsen
ed. Clinical resistance to acyclovir was suspected, and therapy with t
his drug was intensified. The dosage of acyclovir was increased to 45
mg/kg, administered by continuous infusion, and the lesions subsequent
ly resolved. The strain of HSV recovered from the patient showed acycl
ovir-resistance in vitro, using the colorimetric method with neutral r
ed. Herpes simplex virus resistance to acyclovir is rare. It is more c
ommon in immunocompromised patients if subtherapeutic doses are admini
stered in the treatment of chronic persistent forms of infection. When
ever clinical resistance to acyclovir is suspected, the dosage should
be increased to 2 mg/kg per h administered via an infusion pump. If no
improvement is observed in the patient's condition with this regimen,
a phosphorylated medication whose mechanism of action is not dependen
t on viral thymidine kinase, such as foscarnet (phosphonoformic acid),
should be substituted.