CUSTOM DERMATOLOGY SEARCH:
The Scoring Clinical Index for Onychomycosis (SCIO Index)
A. Y. Sergeev, MD, PhD, DMSca,b, A. K. Gupta, MD, PhD, FRCPCc, Y. V. Sergeev, MD, PhD, DMSca,d
Onychomycosis is a common superficial fungal infection, affecting between 6.5 and 12.8% of the population in North America.1 Individuals over 60 years of age are most commonly affected, with prevalence rates as high as 20-30% in this population.1 Toenails are involved to a greater extent than fingernails, and the great toenail is the most commonly affected. The clinical presentation of the onychomycosis, i.e., distal and lateral onychomycosis, superficial white onychomycosis, proximal subungual onychomycosis, and total dystrophic onychomycosis must be taken into account when therapeutic decisions are being made. The Scoring Clinical Index for Onychomycosis (SCIO index) attempts to present the severity of onychomycosis as a composite score.3-6
The SCIO Index
The clinical pattern component of the SCIO is further divided into (1) clinical form, (2) depth of nail involvement and, (3) thickness of subungual hyperkeratosis. The clinical form is taken from Zaias,2 who proposed the classification of onychomycosis into distal-lateral subungual onychomycosis (DLSO), proximal subungual onychomycosis (PSO) and superficial white onychomycosis (SWO). The depth of involvement of the onychomycosis, the degree of hyperkeratosis and the type of clinical presentation are used to calculate SCIO.
These values are then substituted into the equation:
Clinical Index Component = [(d/3)3-f (f + h(3 - f))]1- [(2 - f)(3 - f)/2]
Using this formula, in SWO, PSO and DLSO the values will be 1, 3, and between 1 and 5, respectively.
The SCIO has a growth component in addition to the clinical index component, and this is based on the location of the onychomycosis (fingernail or toenail, digit number) and the age of the patient.
The growth component may reflect the amount of therapy required for onychomycosis. The growth component value reflects approximately the time needed for complete outgrowth of the target nail. The SCIO index (range 1 to 30) is calculated using the clinical index component and the growth component in the following equation:
SCIO = [(d/3)3-f (f + h (3-f)) ( l) (a + 3)/3]1-[(2-f)(3-f)/2]
A higher SCIO index suggests that the onychomycosis may be more severe and thereby require more prolonged treatment. The proposed guidelines for treatment of onychomycosis according to SCIO values are summarized below:
To facilitate SCIO evaluation by clinicians, several utilities have been designed. Among them, is the SCIO ruler - a paper device used to obtain the SCIO values without having to make any calculations. The ruler also provides guidelines for selecting treatment strategy in onychomycosis. The same task may be performed with a SCIO electronic calculator or on a special website available at http://www.onychoindex.com.
The SCIO may enable comparison of the severity of onychomycosis between nails despite differences in the clinical presentation and demographics. The SCIO index may prove to be an accurate indicator of therapeutic effectiveness. However, further clinical studies will be required before definitive claims can be made.
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Last modified: Thursday, 21-Jun-2012 16:51:23 MDT