Top 5 dermatology puzzler case studies of 2025

Welcome to another edition of Countdown to 2026, and thank you for visiting and following Contemporary Pediatrics throughout 2025. In this edition, we present our top dermatology case studies published this year.

Full case: A newborn baby with a rash

A 21-year-old primigravida woman presented to the hospital in preterm labor, with an otherwise uneventful pregnancy except for a febrile illness after exposure to family members with measles a week prior.

She reported having fever, cough, conjunctivitis, and a rash that started on her face and spread to her trunk, consistent with measles. Her fever and symptoms had mostly resolved, except for her lingering rash that began 6 days earlier. In the delivery room, she still had fresh excoriation marks on her arms. She had not received any measles-mumps-rubella (MMR) vaccines.

Click here for the full case and diagnosis.

Can you diagnose this 11-year-old with a petechial rash?

In November 2023, an otherwise healthy 11-year-old boy presented to the clinic with the chief complaint of testicular discomfort. He reported mild testicular pain that worsened with physical activity, and he denied the presence of dysuria, urinary urgency, or frequency. He was recently evaluated by ENT for an episode of epistaxis, which was benign and resolved without requiring cauterization. His medical history was otherwise unremarkable, notable only for molluscum contagiosum at 5 years of age and a few episodes of streptococcal pharyngitis and otitis media.

His vital signs in the clinic were within normal limits, and the only additional finding at this time was a nontender, nonpruritic, and nonpalpable petechial rash on the bilateral lower extremities. His mother observed that the rash appeared to fluctuate with his activity level, worsening during periods of increased stress or activity.

Given the presence of petechiae, an initial workup was initiated, including a complete blood count (CBC), comprehensive metabolic panel (CMP), prothrombin time (PT), and partial thromboplastin time (PTT). A point-of-care urinalysis performed in the clinic revealed traces of blood in the urine. The patient appeared well and did not show any other signs of illness. He was diagnosed with viral epididymitis while pending laboratory results. He was advised to remain hydrated and to return for follow-up if his symptoms persisted or worsened. His mother agreed with this plan and committed to closely monitoring his rash. Click here to guess this patient's diagnosis, and to view the full case.

Full case: 21-month-old with history of “skin tags” on her gluteal cleft

A 21-month-old girl presented with a history of "skin tags" involving her gluteal cleft, noted at birth (Figure 1A). She was otherwise healthy and developing normally. Notably, her older sister had a confirmed history of molluscum contagiosum (MC). Skin exam featured three prominent 2-4 mm soft, pedunculated papules within the superior aspect of her gluteal cleft, as well as sparsely scattered 1-2 mm papules characteristic of MC on the gluteal prominences and in mirror distribution on the perianal mucosa.

Read the full case presentation of a 21-month-old with a history of "skin tags" involving her gluteal cleft, noted at birth.

Full case study: Urticarial rash in a 9-hours-old male

A 6-day-old male with history of waxing and waning urticarial rash presents to the general pediatrician’s office for evaluation. The parents describe the rash as red, raised skin lesions that become flat and congregate, lasting several hours to days, resolving without leaving marks and then appearing in new areas. The rash began shortly after birth, and it does not seem to bother the patient. The parents deny any other concerns, including vomiting, fever, joint swelling, oral ulcers, or irritability. The patient is breastfeeding well and has normal urination and bowel movements.

Click here for the full case, differential diagnosis, and correct case diagnosis.

Can you diagnose this boy with painful nodules on his feet?

A boy aged 10 years presented to the outpatient office with a history of painful nodules on the plantar surface of his bilateral feet 8 to 10 hours after spending time in a hot tub. He was unable to bear weight or put on socks and shoes due to his pain. The photos were taken soon after the painful and red papules appeared. The lesions affected the whole plantar aspect of both feet. Over the following 4 days, the nodules became less painful and red.

Medical advice was sought on the fifth day of symptoms, and by this time, the child was improving clinically. He was stable with subcutaneous, mildly painful, fleshy nodules mostly populating the medial arch of the foot. His remaining clinical examination results were within a normal range. Further questioning of the child’s mother revealed that other children exposed to the hot tub experienced painful feet but without lesions.

Due to the patient’s improving symptoms and the self-limiting nature of the illness, no tests or labs were ordered as the child was not acutely ill. No peer consultations or specialists were utilized.

Click here to guess this patient's diagnosis.