Facial Swelling and Linear Vesicles in a Pediatric Patient

Correct Answer. D. Rhus dermatitis

The most likely diagnosis is rhus dermatitis. Multi-drug-resistant periorbital cellulitis is more likely to present with fever and pain that is more noticeable than pruritus. Erysipelas would also have pain as the predominant symptom and would not have multiple regions of involvement. Eczema herpeticum presents with monomorphic “punched out” skin lesions. Given the patient’s well appearance, absence of systemic symptoms such as fever, chills, or fatigue, and lack of pain or tenderness of the affected area, infectious etiologies were unlikely. The patient complained of pruritus of the involved areas and denied pain. Additional lesions, including some in linear configuration, were also discovered on the patient’s trunk and proximal extremities. The physical examination finding of linear vesicles is classic for rhus dermatitis and is not seen in the other entities. 

Furthermore, the patient's history of camping in the Appalachian Mountains was helpful to identify a likely exposure to Toxicodendron species (commonly known as poison ivy, poison oak, and poison sumac) in the region.¹ Thus, the ultimate diagnosis of rhus dermatitis was reached.

Treatment and management. The patient was started on an oral prednisone taper (1 mg/kg for one week followed by 0.5 mg/kg for 1 week) and topical triamcinolone 0.1% ointment twice a day. 

Outcome and follow-up. The symptoms and rash completely resolved following completion of the prescribed regimen with the patient feeling much better. No further follow-up was needed.

Discussion. Rhus dermatitis is an allergic contact dermatitis caused by urushiol, an oily resin found in Toxicodendron plants. Individuals may encounter urushiol by contacting stems or leaves of these plants when outdoors. The skin then rapidly absorbs this oil due to its lipophilicity. In response to urushiol, the body elicits a Type IV hypersensitivity, or delayed hypersensitivity reaction.¹ This reaction is a T-cell mediated immune response that usually becomes symptomatic about 4 days after exposure.¹

After the first exposure to urushiol, and once the toxin has penetrated the skin, urushiol is oxidized and internalized by antigen presenting cells. The antigen is then presented to CD4 T-helper cells, causing a cascade that leads to formation of T-effector and T-memory lymphocytes.² Patients are not symptomatic after their first exposure. However, following subsequent exposures, the memory lymphocytes (particularly CD8 cytotoxic T-cells) elicit an immune response mediated by cytotoxic granules causing vesicular eruptions, weeping, erythema, epidermal cell destruction, and dermal vasodilation.²

Due to the inflammatory response seen in severe cases of rhus dermatitis, especially in sensitive areas such as the face, eruptions may mimic infectious processes such as periorbital cellulitis when the face is involved. In this patient's case, the exuberant periorbital swelling and erythema initially masked the underlying allergic etiology preceding contact with Toxicodendron plants.

Periorbital cellulitis originates from bacterial invasion of the soft tissues of the eyelid. Common causative microorganisms are Staphylococcus aureus and Streptococcus pyogenes. It is typically acquired by either a minor trauma to the periorbital region that allows infiltration of bacteria, a previous orbital surgery, or an adjacent infection such as a sinusitis that causes local spread.³

This case highlights the importance of obtaining a thorough patient history and comprehensive physical examination to formulate a broad differential diagnosis. It is critical to consider both infectious and inflammatory etiologies as antibiotics may have adverse effects including drug reactions, induction of gut dysbiosis, and photosensitivity (e.g., doxycycline).⁴

Rhus dermatitis accounts for at least 43,000 ED visits and 100,000 clinic visits per year.¹ Anti-inflammatory medications such as corticosteroids are the mainstay of treatment.¹ When oral corticosteroids are administered, it is imperative that the proper duration of taper is utilized to prevent rebound flaring of the rash.⁵ Typically, this can happen around day 7 if steroid administration is stopped too soon and the immune response is still active. A gradual taper over at least 2 weeks prevents rebound inflammation by allowing the dermatitis to fully resolve and match the body's natural tapered immune response.⁵ This ensures safe withdrawal from corticosteroids while also ensuring full clearance of the body's hypersensitivity reaction.⁵

This case demonstrates that a common dermatitis when severe may have overlapping features with more serious etiologies. The authors encourage readers to consider inflammatory conditions in addition to infection with presentations involving erythema of the skin.

AUTHORS:
Julia A. Vaichekauskas, 2d Lt, USAF, MSC¹ • Russell Newkirk, LCDR, MD² • A. Yasmine Kirkorian, MD³

AFFILIATIONS:
¹Air Force Medical Student, Class of 2028, Uniformed Services University
²PGY-4, Dermatology Resident, Walter Reed National Military Medical Center, Children's National
³Chief of Dermatology, Division of Dermatology, Children's National Health System, Associate Professor of Dermatology and Pediatrics, George Washington University School of Medicine and Health Sciences

CITATION:
Vaichekauskas JA, Newkirk R, Kirkorian AY. Facial Swelling and Linear Vesicles in a Pediatric Patient. Consultant. Published online March 5, 2026. doi: 10.25270/con.2026.03.0000001
Received: July 21, 2025. Accepted: September 26, 2025.

DISCLOSURES:
Julia A. Vaichekauskas and Russell Newkirk, MD report no relevant financial relationships. A. Yasmine Kirkorian, MD reports speaker honoraria, consultant or paid advisory board member, research grant on dupilumab, and course director at Oakstone.

DISCLAIMER: The views expressed in this article are those of the authors and do not necessarily reflect the official policy of the Department of Defense or the U.S. Government.

ACKNOWLEDGEMENTS:
None.

CORRESPONDENCE:
Julia A. Vaichekauskas, 2d Lt, USAF, MSC, 4301 Jones Bridge Rd, Bethesda, MD 20814 (Email: julia.vaichekauskas@usuhs.edu)

References

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2. Gladman AC. Toxicodendron dermatitis: poison ivy, oak, and sumac. Wilderness Environ Med. 2006;17(2):120-128. doi:10.1580/PR31-05.
3. Yadalla D, Jayagayathri R, Padmanaban K, Ramasamy R, Rammohan R, Nisar SP, Rangarajan V, Menon V. Bacterial orbital cellulitis – a review. Indian J Ophthalmol. 2023;71(7):2687–2693. doi:10.4103/IJO.IJO_3283_22.
4. Duong QA, Pittet LF, Curtis N, Zimmermann P. Antibiotic exposure and adverse long-term health outcomes in children: a systematic review and meta-analysis. J Infect. 2022;85(3):213-300. doi:10.1016/j.jinf.2022.01.005.
5. Butt M, Flamm A, Marks JG, Flamm A. Poison ivy dermatitis treatment patterns and utilization: a retrospective claims-based analysis. West J Emerg Med. 2022;23(4):481–488. doi:10.5811/westjem.2022.March.55516.

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