Day: July 1, 2019

What is This Itchy Rash?

Patient Presentation
A 12-year-old African-American female came to clinic with a new rash for 2-3 weeks that was intensely pruritic. It was mainly truncal and general lotion applications had not improved her symptoms. Her sleep had been disturbed because of the pruritus and she was now taking diphenhydramine at night. She denied any new soaps, lotions, cosmetics, detergents, insect repellent, sun creams, etc. She also denied any travel, sleeping in others beds, or trying on other people’s clothes or clothing at a store, or furry animal contact. No one else in the household or friends had any similar symptoms.

The past medical history was positive for moderate intermittent asthma when she was younger, but in the past couple of years she was not having any symptoms. The family history was positive for asthma, allergic rhinitis, diabetes and heart disease. The review of systems was otherwise negative.

The pertinent physical exam showed a healthy female with normal vital signs and growth patterns. Her skin reveals a red, extensive, papular rash over her entire trunk, to her hair line, down the top part of her arms and legs, with sparing of the axillary and groin areas. There was no scale or umbilication. There were extensive excoriations but no areas looked to have secondary infection. There was no hypo- or hyper-pigmentation.

The pediatrician was uncertain of the diagnosis and considered scabies because of the intense pruritus but the distribution was not classic and given the time frame it probably would have spread to some of the usual areas. Atopic dermatitis was also considered but there appeared to be little xerosis. Gianotti Crosti was considered too but again the distribution was not appropriate. Contact dermatitis also seemed unlikely. Pictures were taken and dermatology was contacted who made the diagnosisof follicular eczema and prescribed steroid creams and consistent emollient application.
No followup was available.

Discussion
Atopic dermatitis (AD) has a prevalence of 3-5% in the overall U.S. population but is increasing with an estimated 10-15% lifetime risk in childhood. It is even more common in children of color with a prevalence in African-American/black children of 17% and Hispanic children of 14%. Health care utilization data also appears to support more severe disease in children of color also.

Atopic dermatitis or eczema is a common dermatological skin problem which characteristically is a pruritic, papular eruption with erythema. Like most papulosquamous eruptions it often occurs in intertrigenous areas in people with allergic constitutions or with a family history of atopy. Sometimes atopic dermatitis is described as the “itch that rashes.” Rubbing and scratching can lead to excoriation and, over time, lichenification. There can also be secondary infections or changes to the skin pigmentation (hyper- or hypo-) in affected areas. AD does not have scale which occurs in other papulosquamous eruptions such as psoriasis or tinea. Emollients for skin rehydration are a mainstay of treatment. Topical steroids are commonly used to decrease inflammation in affected areas. Immunosuppressants such as tacrolimus are also used in some cases.

Common differential diagnoses include contact dermatitis, keratosis pilaris, nummerular dermatitis, psoriasis, scabies, seborrhea and tinea corporis, but others can also be considered depending on age and circumstances. A more extensive differential diagnosis of AD can be found here. More information about scabies can be found here. Information about Gianotti Crosti can be found here.

For pathologists, a skin biopsy will show spongiosis or intracellular edema in the epidermis with the desmosome junctions being easy to identify. Other classical changes including infiltration with various cells helps to classify typical patterns and specific diagnoses. With atopic dermatitis for example, dermal eosinophils are commonly seen.

Learning Point
Follicular atopic dermatitis is very common in persons of color, particularly African-American, Asian and Hispanic patients. Patients and parents often report severe pruritus but without the eczematous changes. However there is follicular prominence on the trunk and proximal extremities. Mid- to high-potency steroid creams along with emollients usually work in 2-4 weeks. Anti-histamines are often necessary because of the severe pruritus.

AD is known to have genetic variants associated with it. Unsurprisingly, these appear to be different for different populations, and unfortunately large scale genetic data sets have limited representation of African-Americans.

In skin of color, follicular accentuation and lichenification, hyper- or hypo-pigmentation are more common. Prurigo lesions (e.g. itchy nodules) are also more common in skin of color.

In a study of race and dermatological conditions presenting to a general outpatient dermatology clinic, the most common problems were:

  • White/caucasian = benign skin neoplasm (22%), eczema or dermatitis (13%), adnexal disease (11%)
  • African American/black = eczema or dermatitis (22%), adnexal disease (16%), follicular disorders (10%)
  • Asian = eczema or dermatitis (25%), adnexal disease (13%), benign skin neoplasm (12%)
  • Native American = eczema or dermatitis (17%), benign skin neoplasm (17%), adnexal disease (13%)
  • Multiracial = eczema or dermatitis (24%), adnexal disease (17%), benign skin neoplasm (9%)

Eczema or dermatitis included atopic dermatitis, contact or irritant allergy, and nummular dermatitis.

Questions for Further Discussion
1. What are indications for referral to a dermatologist?
2. What are indications for use of a topical steroid cream?

3. What other dermatological problems are more common or severe in persons of color?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Eczema

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Sardana K, Arora P, Mishra D. Follicular eczema: a commonly misdiagnosed dermatosis. Indian Pediatr. 2012 Jul;49(7):599.

Fischer AH, Shin DB, Margolis DJ, Takeshita J. Racial and ethnic differences in health care utilization for childhood eczema: An analysis of the 2001-2013 Medical Expenditure Panel Surveys. J Am Acad Dermatol. 2017 Dec;77(6):1060-1067.

Eichenfield LF, Stein Gold LF. Practical strategies for the diagnosis and assessment of atopic dermatitis. Semin Cutan Med Surg. 2017 Mar;36(2 Suppl 2):S36-S38.

Silverberg NB. Typical and atypical clinical appearance of atopic dermatitis. Clin Dermatol. 2017 Jul – Aug;35(4):354-359.

Gaulding JV, Gutierrez D, Bhatia BK, Han X, Krajenta R, Neslund-Dudas C, Lim HW, Pritchett EN. Epidemiology of Skin Diseases in a Diverse Patient Population. J Drugs Dermatol. 2018 Oct 1;17(10):1032-1036.

Daya M, Barnes KC. African American ancestry contribution to asthma and atopic dermatitis. Ann Allergy Asthma Immunol. 2019 Feb 15. pii: S1081-1206(19)30101-2.

Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa