Case Study: Recurrent Petechiae in an Adolescent Female Following Physical Strain

Case at a Glance

A 17-year-old female with no significant past medical history presented with a three-week history of recurrent petechial rashes. The episodes appeared to be triggered by activities involving physical strain or minor trauma, prompting an evaluation to rule out underlying hematological disorders.

Patient's Story

The patient, a 17-year-old female with an unremarkable medical history and not taking any regular medications, presented with concerns about recurrent spots on her skin over the past three weeks. She reported the first episode occurred after a night of excessive alcohol consumption that led to forceful vomiting. The following morning, she noticed a dense, pinpoint, non-itchy red rash around both eyes. This periorbital rash resolved spontaneously over the course of a week. A few days later, a second episode occurred where she noted a patch of similar spots on her upper thigh. She associated this with a moment of significant physical exertion while upset. The current and presenting episode involved multiple patches of petechiae—six distinct areas of varying sizes on her legs, upper thigh, and left arm. Some patches were small and subtle, while one was described as being nearly the size of her hand. She noted that this outbreak coincided with her scratching numerous mosquito bites in those areas. Worried by the recurrence and varying size of the lesions, she sought medical advice.

Initial Assessment

Upon presentation to the clinic, a thorough history was taken, confirming the timeline and the association of the rashes with Valsalva-like maneuvers (vomiting) and minor trauma (strenuous muscle contraction, scratching). The patient denied other symptoms such as fever, fatigue, weight loss, spontaneous nosebleeds, or bleeding gums. On physical examination, the physician noted multiple, non-palpable, purpuric macules consistent with petechiae and ecchymoses on her extremities. To confirm the nature of the lesions, diascopy was performed (pressing a glass slide against the skin), which revealed they were non-blanching, confirming they were extravasated blood rather than vascular dilation. The periorbital area was clear at the time of examination. Several healing insect bites were visible on her legs and arms, corresponding to the locations of some of the petechial patches.

The Diagnostic Journey

The primary concern was to exclude an underlying disorder of hemostasis, such as thrombocytopenia or a coagulopathy. The link to physical pressure suggested a possible benign mechanical cause, but given the recurrent nature, baseline laboratory tests were essential for a definitive diagnosis. An initial workup was ordered, including:

1. Complete Blood Count (CBC) with Differential: To assess the platelet count, hemoglobin, and white blood cells. A low platelet count (thrombocytopenia) is a common cause of petechiae.
2. Peripheral Blood Smear: To visually inspect platelet size and morphology and to rule out pseudothrombocytopenia (platelet clumping).
3. Coagulation Panel (PT/INR, aPTT): To evaluate for disorders in the clotting cascade.

All laboratory results returned within normal limits. The platelet count was robust, and there was no evidence of anemia or abnormal white cells. Coagulation times were also normal.

Final Diagnosis

Benign Mechanical Purpura (also known as Traumatic Petechiae).

This diagnosis was made based on the clinical presentation of petechiae and ecchymoses appearing at sites of increased intravascular pressure or minor trauma, in conjunction with completely normal hematological lab results. The initial periorbital petechiae after vomiting is a classic sign of Valsalva-induced purpura. Subsequent episodes linked to muscle strain and scratching further supported this diagnosis of exclusion.

Treatment Plan

The core of the treatment plan was patient education and reassurance. The physician explained that the patient's capillaries were slightly fragile and prone to rupturing under direct pressure or strain, but that her blood, platelets, and clotting ability were perfectly normal. No medical intervention was required. The patient was advised that the spots were harmless, would resolve on their own within one to two weeks, and could be minimized by avoiding intense straining activities or harsh scratching. She was also counseled on the risks of binge drinking.

Outcome and Follow-up

The patient was relieved by the normal lab results and the benign diagnosis. She was advised to return to the clinic if she experienced spontaneous, widespread petechiae without a clear traumatic cause, or any signs of abnormal bleeding (prolonged nosebleeds, blood in urine/stool, bleeding gums). At a follow-up call two weeks later, she reported the existing spots had faded completely. She had a better understanding of the triggers and felt less anxiety about the condition.