Cutaneous Manifestations of Sexually Transmitted Infections: A Visual Guide

Skin findings can be the presenting clue for STIs. Key patterns by pathogen:

Syphilis (Treponema pallidum)

• Primary: Painless chancre (clean‑based ulcer) at inoculation site.
• Secondary: Diffuse maculopapular rash (incl. palms/soles), condyloma lata, mucous patches, alopecia.

Herpes Simplex (HSV‑1/2)

• Grouped vesicles on erythematous base → painful ulcers; recurrent at same dermatome.

Human Papillomavirus (HPV)

• Genital warts: flesh‑colored, cauliflower‑like, flat or pedunculated.

Molluscum Contagiosum

• Umbilicated, pearly papules; often intertriginous or genital.

Pubic Lice (Pthirus pubis)

• Pruritus; nits/lice on pubic hair; excoriations.

Scabies (Sarcoptes scabiei)

• Burrows, papules, intense nocturnal itch; finger webs, wrists, beltline, genitalia.

Chancroid (Haemophilus ducreyi)

• Painful, soft, undermined ulcer + tender suppurative inguinal adenopathy.

Granuloma Inguinale (Donovanosis)

• Beefy‑red, bleeding, progressive ulcers; painless.

Lymphogranuloma Venereum (LGV)

• Transient painless papule/ulcer → suppurative buboes.

Secondary Bacterial Infections

STI‑disrupted skin → impetigo, cellulitis, abscess.

Action

Any suspicious genital/perianal lesion → NAAT/swab/darkfield/biopsy per guideline; partner notification/treatment.