Differences in Response to Topical Irritants in Haired and Hairless Guinea Pigs

Abstract

The hairless guinea pig offers the possibility of performing irritant studies without the use of depilatory agents or clipping. Studies have shown a response to allergens and simple irritants comparable to that of the haired guinea pig but with differences depending on substance and concentration used. Histoanatomical studies have demonstrated differences in cutaneous structure in the two strains, differences that might influence the response to complex low‐grade irritants such as composite vehicles. The purpose of this study was to compare the usability of hairless (HLGP) and clipped haired guinea pigs (CGP) in tolerability studies of composite formulations. The tolerability of six selected skin care formulations (SCF), known to cause a differentiated irritative response in the HLGP, was studied in 15 male CGPs and 15 male HLGPs. All animals were treated on a 5 × 5 cm area on each side of the dorsal trunk twice daily for 4 consecutive days with SCF. The tolerance of the different SCF was assessed by clin...