The skinfolds of the body include the groin, intergluteal cleft,
axilla, inframammary, and pannus regions. The skinfolds have unique
characteristics that set them apart from other regions of the body.
For one, these areas are almost continuously occluded. As a result,
scale does not develop; maceration and fissuring develop instead.
This situation alters the appearance of papulosquamous diseases
and inflammatory processes. The occlusion also allows for the development
of a warm, moist environment favorable to the growth of fungi, yeast,
and bacteria. Although many skin diseases can affect the skinfolds
to some degree, this chapter focuses on common disorders where skinfold
eruptions are the main finding.
An important point for treatment of intertriginous diseases
is avoiding combination corticosteroid/antifungal products. Although
processes in the groin folds can be confusing and complicated by
secondary change, using combination products may further cloud the
clinical picture. If improvement is seen, it is difficult to ascertain
which medication prompted the change. And, finally, the corticosteroid
component of these medications is too strong to be used in the occluded
intertriginous skin, and may produce irreversible striae with long-term
This chapter discusses common infections, infestations, sexually transmitted
diseases, and inflammatory and reactive conditions that involve
the groin and skinfolds.
Tinea cruris is a fungal infection of the groin commonly called “jock
itch.” It is very common in males, uncommon in
females, and exceedingly rare in children. Tinea cruris results
from invasion of the stratum corneum by the dermatophyte types of
fungi (see Box 247-2 in Chapter 247, Disorders of the Hands, Feet, and Extremities). It is
transmitted via direct contact [person to person, or animal (usually
kittens or puppies) to person] or fomites.
Examination is significant for symmetric erythema with a peripheral
annular slightly scaly edge (Figure 248-1).
The groin is typically involved, and the process may extend onto
the inner thighs and even the buttocks. The penis and scrotum are
spared, a distinguishing feature of tinea cruris, as most other
eruptions will affect the scrotum. Frequently, tinea pedis is also
found and may be spread from the feet to the groin through putting
Tinea cruris. Note raised, sharp-edged margins. (Reproduced with
permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s
Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005,
McGraw-Hill, New York.)
Scraping the leading edge and performing a potassium hydroxide
(KOH) examination will demonstrate branching hyphae, unless the
patient has recently applied topical antifungal preparations (see Box 247-3 in Chapter 247, Disorders of the Hands, Feet, and Extremities). If a KOH examination
is negative, one of the other above-mentioned disorders discussed
in this chapter (Table 248.01) should be