Adult-Gerontology Clinical Nurse Specialist (CNS) Practice Exam

If a patient has large red nodules draining pus in the pit of his arm, which condition is likely?

1. Early Lyme disease

2. Pityriasis rosea

3. Scabies

4. Hidradenitis suppurativa

The correct answer is: Hidradenitis suppurativa

Hidradenitis suppurativa is often characterized by painful, inflamed nodules and abscesses that can drain pus, commonly occurring in areas with numerous sweat glands, such as the armpits, groin, and under the breasts. The presence of large red nodules that are draining pus in the pit of the arm aligns with the typical presentation of this condition. In hidradenitis suppurativa, the nodules can become recurrent and tend to form tunnels under the skin, leading to further complications, which are not typically seen in the other listed options. Understanding the etiology involves recognizing that this condition is likely influenced by factors such as genetic susceptibility, obesity, and inflammation related to hair follicles. Other conditions mentioned can present with skin lesions but do not specifically align with the features described. For instance, early Lyme disease typically presents with a characteristic "bull's-eye" rash, scabies is known for intense itching and burrows, and pityriasis rosea usually involves a herald patch followed by a distinctive rash pattern. Thus, the distinct features and location of the lesions strongly suggest hidradenitis suppurativa as the most appropriate diagnosis in this scenario.