The dermatologic conditions of the feet are similar to those of the hands. Inflammatory conditions such as psoriasis and eczema often mirror palmar disorders. Similarly, bacterial, viral (e.g., warts), and fungal infections are also prone to appear on the feet (see Hands and Fingers and Nails). Warts and other benign lesions must be distinguished from the rare, but potentially fatal, acral lentiginous melanoma.

Tinea Pedis

Distinguishing Features

Acute interdigital tinea pedis is seen predominantly in males between 18 and 40 years of age. It is most often caused by T. mentagrophytes.

  • Scale, maceration, and fissures of toe webs are characteristic, especially between the fourth and fifth toes (Fig. 19-1); however, any web space, as well as the dorsal foot may be involved

  • Often asymptomatic; however, it may itch intensely

  • Marked inflammation and fissures suggest bacterial superinfection

  • Clusters of pruritic vesicles, bullae, or pustules on the sides of the feet, insteps, toes, or soles (Fig. 19-2)

Chronic tinea pedis is caused by T. rubrum (see also Hands and Fingers).

Distinguishing Features

  • “Moccasin” distribution consists of scales covering the sole and sides of the feet (hyperkeratotic/moccasin type, usually caused by T. rubrum)

  • The skin of the entire sole, sides of the foot, and heel is scaly, appears to be “dry,” but not inflamed (Fig. 19-3)

  • Borders are distinct along the sides of the feet and may extend to the Achilles area (Fig. 19-4)

  • There is often nail involvement (onychomycosis)

  • Symptoms are minimal unless painful fissures occur

  • Palmoplantar tinea can be present on one or both palms (tinea manuum), as well as on both soles (“two feet, one hand” tinea). This is pathognomonic for tinea (see Fig. 14-18)

Plantar Warts

Distinguishing Features

  • A loss of normal skin markings (dermatoglyphics) such as footprints and toeprints

  • Lesions may be solitary or multiple, or they may appear in clusters (mosaic warts) (Fig. 19-5)

  • Can be tender and painful

  • Extensive involvement on the sole of the foot may impair ambulation, particularly when present on a weight-bearing surface

Jan 8, 2023 | Posted by in Dermatology | Comments Off on Feet

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