Idiopathic Pruritus Ani and Acute Perianal Dermatitis

Abstract

This article reviews the etiologies, pathophysiology, clinical evaluation, and treatment of idiopathic pruritus ani and perianal dermatitis. It underscores a practical approach to each of these common proctologic conditions.

Keywords: contact; dermatitis; diagnosis; idiopathic; irritant; pruritus ani; treatment.

Fig. 1

Illustrates fecal debris, mild erythema, and mixed hemorrhoids at the anal verge of a male with pruritus ani. (This image is provided courtesy of A. Ortega.)

Fig. 2

The itch–scratch cycle of idiopathic pruritus ani and potentially inciting and mitigating factors is illustrated. These events are progressive clinically constituting a vicious cycle.

Fig. 3

Severely excoriated and macerated tissues are evident within the anal margin representative of one extreme of the itch–scratch cycle. (This image is provided courtesy of A. Ortega.)

Fig. 4

Lichen simplex is the chronic presentation of pruritus ani. Thickening of the anal verge tissues and deepening of the rugal folds may be apparent as well as concentric superficial radial fissuring. (This image is provided courtesy of I. Khubchandani.)

Fig. 5

The Whitehead deformity following hemorrhoid surgery exemplifies a surgical cause of pruritus ani diagnosed on physical examination. (This image is provided courtesy of A. Ortega.)

Fig. 6

(a) Extensive appendages (skin tags) within the anal verge. (b) A conglomerate of hypertrophic papillae, papillomas, and skin tags is in evidence. Both examples when associated with pruritus ani may benefit from surgical resection to facilitate local hygiene. (These images are provided courtesy of A. Ortega.)

Fig. 7

Erythema and reactive edema in the perianal eczema (This image is provided courtesy of X. Delgadillo.)

Fig. 8

Synchronous body itch–scratch–lichenification cycle in case of chronic dermatitis involving (a) nails, (b) fingers, (c) inframammary folds, and (d) perianal region. (These images are provided courtesy of X. Delgadillo.)