What are the causes of nodular ecchymoses in children?

Causes of Nodular Ecchymoses in Children

Nodular ecchymoses in children most commonly result from lichen sclerosus (particularly in the anogenital region), acute hemorrhagic edema of infancy, vitamin K deficiency bleeding, or solitary mastocytoma—each presenting with distinct clinical patterns that guide diagnosis.

High-Priority Dermatologic Causes

Lichen Sclerosus

• Ecchymosis can be strikingly prominent in prepubertal children with anogenital lichen sclerosus, often mimicking signs of sexual abuse 1, 2
• Typical lesions appear as porcelain-white papules or plaques accompanied by areas of ecchymosis in the interlabial sulci, labia minora, clitoral hood, and perineal body 1
• Perianal involvement occurs in approximately 30% of female cases and may present with constipation due to painful fissuring 1
• Critical pitfall: Lichen sclerosus and sexual abuse are not mutually exclusive; the disease exhibits the Koebner phenomenon, producing lesions at trauma sites 1, 2
• Red-flag features suggesting possible concurrent abuse include: older prepubertal age, poor response to standard therapy, coexisting sexually transmitted infections, or additional clinical signs of maltreatment 2

Acute Hemorrhagic Edema of Infancy (AHEI)

• Presents in children aged 4-24 months with rapid onset of small erythematous macules or papules that progress to well-demarcated, annular, rosette, medallion-like, or targetoid purpuric plaques or ecchymosis within 24-48 hours 3
• The skin lesions are typically palpable, nonpruritic, and symmetrically distributed on the face, auricles, and extremities 3
• Accompanied by nonpitting, asymmetrical edema primarily on the dorsum of hands and feet, face, and auricles 3
• Key distinguishing feature: Despite acute and extensive cutaneous findings, the child appears well and nontoxic 3
• Fever is low-grade and present in approximately 50% of cases, often with prodromal upper respiratory infection symptoms 3
• This is a benign, self-limited disease with complete spontaneous recovery in 1-3 weeks in the majority of cases 3

Solitary Mastocytoma

• Typically presents at birth or within the first week of life as a single lesion that can blister and form bullae, especially in interdigital locations where friction occurs 4
• Rapid progression from a papule to a hemorrhagic bulla within one day is characteristic 4
• Darier's sign (wheal and erythema after gently rubbing the lesion) confirms the diagnosis 4
• Interdigital lesions in areas prone to maceration and friction are high-risk sites for ulceration and bullae formation 4
• Systemic symptoms such as fever are absent, and visceral involvement is rare 4

Life-Threatening Hematologic Causes

Vitamin K Deficiency Bleeding (VKDB)

• Can present as multiple purpuric and nodular non-collapsible swellings, though this is not the most common presentation 5
• Occurs most commonly in exclusively breastfed infants who did not receive vitamin K prophylaxis at birth 2, 5
• Investigations reveal prolonged PT and possibly aPTT, with normal fibrinogen levels and platelet counts 2, 5
• Critical to recognize early: Late VKDB usually presents as intracranial or mucosal hemorrhages, which can be fatal 5
• Skin and mucosal bleeding may occur in one-third of infants with VKDB 5

Inherited Bleeding Disorders

• Von Willebrand disease is the most common inherited bleeding disorder (prevalence approximately 1 in 1000), presenting with mucocutaneous bleeding and easy bruising 2
• Important limitation: Normal PT/aPTT does not exclude von Willebrand disease, Factor XIII deficiency, or platelet function disorders 2, 6
• Hemophilia (Factor VIII or IX deficiency) can cause significant bruising even with mild deficiencies, particularly concerning in males 2
• Immune thrombocytopenia (ITP) is a transient, often self-resolving disorder characterized by low platelet count 2

Other Nodular Lesions to Consider

Congenital Melanocytic Nevi (CMN)

• Can present with nodules within the nevus, though these are typically pigmented rather than ecchymotic 1
• Changes within CMN may include becoming more raised, hypertrichotic, verrucous, cerebriform, mamillated, or papillated over time 1
• Increased fragility may result in ulcerations, erosions, and bleeding with minimal trauma 1

Cutaneous Leishmaniasis

• Lesions may be nodular or ulcerative with well-defined, often indurated borders 1
• Regional adenopathy and subcutaneous nodules in a lymphatic drainage "sporotrichoid" pattern may occur 1
• Lesions typically begin as papules, progress in size, and often ulcerate 1

Erythema Nodosum

• Presents as tender, erythematous nodules typically on the lower extremities 7
• In children, streptococcal infections (usually pharyngeal) are the most common cause (22%), followed by Yersinia infection (15%) 7
• Differential diagnosis pitfall: Nodular vasculitis and Henoch-Schönlein purpura must be excluded by pathologic study in cases of atypical presentation or long duration 7

Diagnostic Approach Algorithm

Initial Assessment

1. Determine distribution pattern: Anogenital (consider lichen sclerosus), face/extremities with edema (consider AHEI), solitary interdigital (consider mastocytoma), or generalized (consider bleeding disorder) 1, 4, 3
2. Assess child's general appearance: Well-appearing with extensive lesions suggests AHEI or mastocytoma; ill-appearing suggests bleeding disorder or infection 3
3. Elicit Darier's sign: Positive in mastocytoma 4

Laboratory Evaluation When Indicated

• Complete blood count with platelet count and peripheral smear 2, 6
• PT and aPTT to detect most factor deficiencies (but not VWD or Factor XIII deficiency) 2, 6
• If bleeding disorder suspected with normal PT/aPTT: Obtain VWF antigen, VWF ristocetin cofactor activity, and Factor VIII activity 2, 6
• Fibrinogen concentration and thrombin time to detect fibrinogen defects 2

Critical Pitfalls to Avoid

• Do not assume normal PT/aPTT rules out bleeding disorders—these tests miss von Willebrand disease, Factor XIII deficiency, and platelet function disorders 2, 6
• Do not dismiss lichen sclerosus as excluding sexual abuse—the two can coexist through the Koebner phenomenon 1, 2
• Do not perform extensive investigations in well-appearing infants with localized purpura/petechiae—observation for 4 hours may be sufficient if no progression occurs 8
• Recognize that vitamin deficiencies (C, K, E, B12) can present with extensive ecchymoses without classic features of scurvy 9