Case Study: Sudden Appearance of Painful Pustules in Patient With Eczema

"Medical Journeys" is a set of clinical resources reviewed by doctors, meant for physicians and other healthcare professionals as well as the patients they serve. Each episode of this journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.

This episode: A noteworthy case study.

Why has this 63-year-old long-time eczema patient suddenly developed painful pustules along with eczematous scaling on the back of his hands and elbows, right forearm, and back? That's the diagnostic challenge facing Daniela Kroshinsky, MD, MPH, of Massachusetts General Hospital in Boston, and colleagues.

As they described in JAAD Case Reports, the patient noted that he had had atopic dermatitis (AD) since childhood. The condition was well controlled and rarely flared up, but when it did, he used clobetasol propionate ointment 0.05% and "999 itch-relieving ointment," a topical compound from China with active ingredients including 1% menthol, 1% synthetic camphor, and 0.075% dexamethasone acetate.

The patient, a correctional officer at a hospital, noted that his institution had recently treated two cases of mpox, but those patients were not on the floor where he worked and he had not had any direct contact with them, nor had he traveled or had contact with animals. He also said he had not engaged in sexual activity with men or outside his marriage, and he did not have any immunocompromising conditions.

He did remember that 2 days before the rash developed, he had become feverish and fatigued and began having chills, muscle aches, and headaches. Appearance of the first vesicular and pustular eruptions on his fingers and palms prompted him to seek care.

On physical examination, clinicians noted "swollen hands with over-lying eczematous changes, including erythematous scaling, purulent and serous oozing, and crusted patches." He also had reddened papules and pustules on his hands, arms, back, and legs, although his mucosa, face, and genitals were unaffected. His lymph glands were normal.

The team performed a biopsy of the anterior proximal right arm, with findings that suggested a viral process. The authors then ordered a nonvariola orthopoxvirus DNA polymerase chain reaction test of the lesion on the patient's left palm, which was found 6 days later to be reactive. Clinicians advised the patient to self-isolate until the lesions cleared, and 3 weeks later, he reported that his skin had cleared.

Discussion

As Kroshinsky and co-authors noted, the incidence of West African clade mpox has been increasing since May 2022, and they believe that their case is the first reported of eczema mpoxicum in the literature, illustrating the relative susceptibility of patients with AD to transmission and the potential environmental stability of the virus.

This case is unique in not involving any of the common routes of exposure, the authors said -- for example, possible occupational transmission via fomites, combined with the patient's increased susceptibility due to having eczema. Also, the patient's early symptoms occurred on his hands rather than the mucosa or face, the typical sites of initial mpox symptoms.

This was likely due to AD-related barrier impairment and masking of the rash's initial morbilliform stages, which delayed the presentation until it had become pustular. The team noted that although this patient had a relatively low risk of exposure, a German study of hospital surface contamination identified traces of viral DNA in hallways outside of mpox isolation rooms. "As such, our case highlights the importance of appropriate personal protective equipment and disinfection in preventing transmission in health care settings," Kroshinsky and co-authors said.

In AD and other conditions that disrupt the skin barrier, developing a superimposed infection can have serious complications, the team noted. A well-documented example of this in AD, they said, is eczema herpeticum, in which herpes simplex virus has led to disseminated infection, encephalitis, hepatitis, and death even in immunocompetent patients.

The effect of disseminated mpox due to superinfection of AD on the severity of the disease is unclear, Kroshinsky and co-authors said. Although West African clade mpox tends to be self-limited, the mortality rate is about 3%, with young children and immunocompromised individuals at greatest risk.

Considering the relatively high proportion of children who have eczema, and the fact that those with severe AD may be taking immunosuppressive medications, the team cautioned that these groups may be at a greater risk of contracting mpox and adverse events than previously realized.

Kroshinsky and co-authors concluded by emphasizing that the risk of mpox is not limited to any one demographic, and that a characteristic rash should prompt thorough evaluation.

Read previous installments in this series:

Part 1: Atopic Dermatitis: Reasons for Optimism

Part 2: Atopic Dermatitis: The Latest on Diagnosis and Assessment

Part 3: The Many Ways to Measure the Severity of Atopic Dermatitis

Part 4: Case Study: Why Is This Young Boy's Atopic Dermatitis So Resistant to Treatment?

Part 5: Atopic Dermatitis Has Myriad Life-Altering Comorbidities

Part 6: Topical Therapies for Adult Atopic Dermatitis

Part 7: Improving Treatment Adherence in Atopic Dermatitis