Likely Etiology

Literature Support



Systemic signs: fever, elevated white count.

Given the distant site from the injection and lack of systemic signs and symptoms, infection seemed unlikely

Allergic reaction (to one or more agents)

Symptoms may range from blanching of the skin to urticarial lesions along the distribution of placement.

Prep, drape, tape, or bandages

Steroid use

Acute generalized exanthematous pustulosis 2 days after SQ injection of dexamethasone.

Local irritation (topical agents)

Capsaicin causes local vasodilation and inhibits both autonomic and somatic nerves. Capsaicin at concentration of at least 0.1%, has shown to penetrate into a collagen mixture and be cytotoxic to both keratinocytes and fibroblasts.

Our patient used capsaicin cream 0.125% on the open lesion.

Heating pads

Heating pad can result in a thermal burn. High risk in elderly patients, and patients with sensory deficits, atrophic skin, vascular insufficiency.


Case reports of third degree burn from interferential current therapy using the TENS machine and cutaneous irritation and contact dermatitis from pad placement.