ABIM Exam Review Practice Question of the Week: Rash in 39-year-old female with hypothyroidism

This week’s sample ABIM Exam Review Question comes directly from the Knowmedge QVault which covers topics listed on the ABIM Board Exam blueprint. It can also be found in the Knowmedge’s Free ABIM Exam Review Questions eBook.

Question

39-year-old female with a history of hypothyroidism presents for a routine follow-up visit. On review of systems, she reports feeling a little “more down” than usual. You review routine labs revealing a 25-hydroxy vitamin D level that is low at 6ng/mL. She also has some mild elevation in her liver function tests. Her lipid panel shows an elevation of her LDL despite being on a very strict low fat diet. She has mild microcytosis on her complete blood count (CBC) test. Thyroid stimulating hormone (TSH) levels come back at 14μU/ml and free T4 at 0.4ng/dL. The patient is very concerned because she has been taking her thyroid pills regularly with a full glass of water, on an empty stomach, and at least 30 minutes removed from her daily vitamin pill. She is also concerned about a rash that has developed on her stomach. Based on the most likely etiology of this patient’s condition, which rash is associated?

A. Lichen planus

B. Contact dermatititis

C. Dermatitis herpetiformis

D. Poison ivy dermatitis

E. Acne rosacea

ABIM Exam Review Question Explanation

This patient has a history of hypothyroidism and despite being compliant with her medications, she is not euthyroid. She also has low 25-hydroxy vitamin D levels (indicating malabsorption), asymptomatic elevation in liver function tests, increased LDL and microcytosis. These signs may be pointing to the presence of malabsorption. She also says she “feels down.” With certain autoimmune diseases such as hypothyroidism, people can also have celiac disease. Celiac disease does not necessarily present with gastrointestinal symptoms but is a systemic disease that can cause neuropsychiatric symptoms and various lab abnormalities. In this patient, the best next step is to check for antibodies against celiac disease. The rash associated with celiac disease is Choice C (Dermatitis herpetiformis), which is an extremely itchy rash that is made up of blisters and bumps.

Let’s review the other answer choices:
● Choice A (Lichen planus) can be associated with NSAID use and cutaneous graft versus host reaction.
● Choice B (Contact dermatitis) is a type IV hypersensitivity reaction that is associated with allergens such as nickel and chromium.
● Choice D (Poison ivy dermatitis) is an itchy rash that occurs, for example, when people are out in the garden or yard and exposed to uroshiol oil-containing plants. It is also an example of type IV hypersensitivity.
● Choice E (Acne rosacea) is an acne-like lesion on the face in middle-aged women, exacerbated by sun exposure.

You can view all the previous ABIM Exam Review Questions of the Week at the Knowmedge Blog. You can also find additional topics and questions directly from the Knowmedge Internal Medicine ABIM Board Exam Review Questions QVault.