Differentials

Perianal fistula

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

The opening is located in the perianal region, and the skin of the natal cleft is normal. Perianal fistulas track toward the anus; pilonidal sinuses track toward the midline of the natal cleft. Patients with a fistula may report rectal discharge of mucus.

INVESTIGATIONS

There are usually no differentiating tests. Diagnosis is clinical. Rarely, an MRI pelvis may be needed to differentiate the etiology.

Perianal abscess

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Patients report severe pain near the anal or rectal area as opposed to the natal cleft. The abscess develops in the perianal region, and the skin of the natal cleft is normal.

INVESTIGATIONS

There are usually no differentiating tests. Diagnosis is clinical.

Hidradenitis suppurativa

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Chronic follicular occlusive disease located in the perineal or inguinal area. Natal cleft area is spared. May also involve the axillary and inframammary regions.

INVESTIGATIONS

There are usually no differentiating tests. Diagnosis is clinical.

Skin abscess/ furuncle/carbuncle

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Collections of pus within the dermis and deeper skin tissues or within the hair follicles. Commonly located away from midline and do not have an associated sinus tract.

INVESTIGATIONS

There are usually no differentiating tests. Diagnosis is clinical.

Folliculitis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Infection within hair follicles and purulence within the epidermis. Commonly appear as multiple small, raised, pruritic, erythematous lesions <5 mm in diameter. Pustule may be visualized within the center of the lesion.

INVESTIGATIONS

There are usually no differentiating tests. Diagnosis is clinical.

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