How to Tell the Difference Between Nummular Eczema and Ringworm
It’s often difficult to distinguish between nummular eczema and ringworm, so it’s always best to be evaluated by a dermatologist, say experts.
Published On: Jan 2, 2024
Last Updated On: Feb 20, 2024
In this edition of Ask the Ecz-perts, we get the lowdown on how people with eczema can care for hypopigmentation, which is light spots of the skin. Our experts talk about causes of the light spots and how you can treat them.
Our experts include: Dr. Nada Elbuluk, associate professor of clinical dermatology and director of the Skin of Color & Pigmentary Disorders Program at Keck Medicine of USC in Los Angeles; and Dr. Zelma Chiesa Fuxench, assistant professor of dermatology at the Hospital of the University of Pennsylvania in Philadelphia.
Dr. Nada Elbuluk: Hypopigmentation is lightening of the skin. We all have pigment in our skin called melanin. When someone has areas that are hypopigmented, they have a reduction in melanin in those areas. Now, that is in contrast to what’s called depigmentation, where someone has complete loss of melanin. It’s important to know that with hypopigmentation, there still is some melanin in there, but it’s less than the normal amount.
Dr. Zelma Chiesa Fuxench: Melanin is what gives skin its pigmentation or color.
Dr. Elbuluk: Hypopigmentation in and of itself is not a disease. Not all light spots are the same thing. It’s really important that people who are experiencing hypopigmentation have it evaluated to know if it is just a result of eczema that will improve with time, or if it is another active condition that needs its own treatment.
Dr. Chiesa Fuxench: There are various skin conditions in which the presenting sign is hypopigmentation, for example idiopathic guttate hypomelanosis or leukoderma punctata. But it may also occur as a result of an acquired process, such as that seen in patients with inflammatory skin conditions like eczema. In this setting, it is often referred to as postinflammatory hypopigmentation or PIH. Other conditions that may result in PIH include traumatic conditions, for example, burns and iatrogenic infection or injury, which is illness unintentionally caused by a healthcare provider or medical procedure. Examples of procedures that may result in PIH are skin peels, laser treatments and cryotherapy, to name a few.
Dr. Elbuluk: There’s also what we consider a type of eczema called pytiriasis alba, where people get light or hypopigmented scaly spots. We tend to see it more in children, specifically children of color.
One other condition that is important for people to know is something called hypopigmented mycosis fungoides, which is a type of skin cancer that can present also with light scaly spots. This happens more in people of color. Many times, people are misdiagnosed as having eczema for many years before it’s actually figured out that they have hypopigmented mycosis fungoides.
Dr. Chiesa Fuxench: Patients with eczema may develop PIH as a result of chronic, ongoing skin inflammation. However, we do not know if patients with eczema may be more predisposed to developing PIH compared to patients with other inflammatory skin disease like psoriasis.
Dr. Chiesa Fuxench: Unfortunately, treatment options for PIH are limited. In the case of acquired PIH, the main goal of treatment should be to identify and treat the cause. Oftentimes, this is enough to help improve this condition and could lead to resolution of PIH in weeks or months.
Options for treatment previously reported in the literature in a small number of studies and with mixed results include topical therapies, such as calcineurin inhibitors (e.g., pimecrolimus cream 1%) or light-based therapies.1,2 Other options include the use of camouflage makeup to help cover lesions, but this may not be feasible due to cost or for patients with extensive surface involvement.
Dr. Elbuluk: Treatment is so important for me as someone who lives in a pigmentary world. A lot of people think that all light spots or all dark spots are the same thing. I often get the question, “How do you treat dark spots?” or “How do you treat light spots?” And it’s not that linear because you have to know what’s causing it. There are many different conditions that can cause each of those, and then you can have a more nuanced conversation about treatment based on the cause.
We have less treatments for light spots than we do for dark spots. We have a lot of creams to lighten dark spots. But usually with light spots, if there’s no active eczema there, it’ll get better on its own with time and gentle skincare. Your body naturally wants to go back to making pigment. For patients who have eczema who are doing phototherapy or light therapy, the light can actually help stimulate the pigment to come back faster, as well.
Dr. Nada Elbuluk is associate professor of clinical dermatology and director of the Skin of Color & Pigmentary Disorders Program at Keck Medicine of USC in Los Angeles.
Dr. Zelma Chiesa Fuxench is assistant professor of dermatology at the Hospital of the University of Pennsylvania in Philadelphia.
References:
1. Saleem MD, Oussedik E, Picardo M, Schoch JJ. Acquired disorders with hypopigmentation: A clinical approach to diagnosis and treatment. J Am Acad Dermatol. 2019;80(5):1233-1250.e10. doi:10.1016/j.jaad.2018.07.070
2. Madu PN, Syder N, Elbuluk N. Postinflammatory hypopigmentation: A comprehensive review of treatments. J Dermatolog Treat. 2022;33(2):704-708. doi:10.1080/09546634.2020.1793892
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