Infantile cortical hyperostosis

Infantile cortical hyperostosis is a rare, self-limited inflammatory disorder of bone and overlying soft tissue, characterized by episodic subperiosteal new bone formation that typically begins within the first five to six months of life.[1][2] The mandible is the single most frequently affected bone, so the condition is of direct relevance to oral and maxillofacial practice, although the diaphyses of the long bones, clavicles, ribs, and scapulae are also commonly involved.[2][3] Episodes couple acute hyperirritability, fever, and painful soft-tissue swelling with striking cortical thickening of the affected bone, then remit spontaneously, with the excess bone resorbed through remodeling, usually by age two years.[1][2][4]

A subset of familial, autosomal dominant cases is caused by a heterozygous missense variant in the gene encoding the α1 chain of type I collagen (COL1A1), placing the disorder among the collagenopathies, though most sporadic cases lack an identified variant.[5][6][7] The signature imaging appearance is florid, layered subperiosteal bone deposition producing a markedly expanded, sclerotic mandible, and management is predominantly supportive.[1][3]

The condition is most often called Caffey disease or infantile cortical hyperostosis (ICH), after the 1945 description by Caffey and Silverman.[1] Caffey-Silverman syndrome and the older De Toni-Caffey disease are accepted synonyms.[8]

A clinically important distinction separates classic ICH from prenatal (antenatal) cortical hyperostosis (PCH), a more severe disorder with onset before roughly 35 weeks of gestation, often accompanied by polyhydramnios, hydrops, and a lethal or near-lethal course.[9][10] On the basis of radiographic and clinical features, some authors argue PCH is a separate entity, proposing that the term Caffey dysplasia be reserved for the prenatal form and Caffey disease for the classic infantile form.[11] This article addresses the classic postnatal entity; the prenatal form is noted only where it aids differentiation.

ICH is rare, and its recognized incidence has fallen markedly since the mid-20th century; nonfamilial case reports have become uncommon in recent decades.[1] There is no established sex or racial predilection.[3][4]

Key distribution and demographic patterns:

• Age of onset: typically between birth and five months, with a mean around nine weeks; onset after one year defines late or recurrent presentations.[1][3]
• Anatomic distribution: the mandible is involved in roughly 70% to 90% of cases, usually the angle and ascending ramus. Other common sites are the clavicle, ribs, scapulae, and long-bone diaphyses.[1][2][3]
• Familial versus sporadic patterns: sporadic cases predominate and more often involve the mandible, whereas familial (autosomal dominant) cases more often involve the tibia and tend to spare the ribs and scapulae.[1][3]
• Inheritance: familial disease shows autosomal dominant inheritance with incomplete penetrance (reported near 79%) and variable expressivity; more than 20% of familial cases are symptomatic at birth.[1][3]

ICH presents acutely in an otherwise previously well infant with the triad of hyperirritability, fever, and firm, tender soft-tissue swelling over the affected bone.[1][2] Swelling is deep and brawny, usually without prominent erythema, and the infant resists manipulation of the area.[1]

Maxillofacial presentation

Mandibular involvement produces unilateral or bilateral facial swelling, frequently centered over the angle and ramus, and can mimic parotitis, cellulitis, or osteomyelitis.[3] Swelling may be clinically unilateral even when imaging shows bilateral bony change.[3] Feeding difficulty and poor weight gain are characteristic complications of mandibular disease, driven by pain on sucking and jaw movement.[3]

Tempo and course

Individual episodes last approximately two to three months and resolve spontaneously.[1] The overall disorder is self-limited, with clinical and radiographic improvement generally by age two to three years.[2][10]

Laboratory findings

Studies are supportive but nonspecific: mild leukocytosis, elevated erythrocyte sedimentation rate and C-reactive protein, and occasionally raised alkaline phosphatase.[1][3]

Red flags and complications

• Recurrence of swelling, pain, and fever, sometimes into childhood or adolescence, is well recognized and may affect new or previously healed sites.[2][12]
• Persistent deformity is uncommon; bowing or fusion of adjacent bones (ribs, forearm, or leg) can occasionally produce lasting mechanical problems.[4][8]
• Features suggesting an alternative serious diagnosis include weight loss, night sweats, painless lymphadenopathy, a focal destructive lesion, or signs of trauma.[3]

Imaging is the cornerstone of diagnosis; characteristic findings combined with the clinical picture are usually sufficient, and biopsy is generally unnecessary.[1][3] In the jaws the hallmark is exuberant subperiosteal new bone that massively thickens the cortex.

Location and distribution in the jaws

• Disease centers on the mandibular angle and ascending ramus, the most consistently involved facial site.[3]
• Involvement may be unilateral or bilateral; bilateral bony change is common even when swelling appears clinically one-sided, so the contralateral mandible should be scrutinized.[3]
• The maxilla is rarely involved relative to the mandible; when facial disease is present, it is overwhelmingly mandibular.[3][11]

Relationship to teeth and the alveolar process

• The process is periosteal and cortical, arising from the outer surface of the ramus and body rather than from the tooth-bearing alveolus.
• There is no primary odontogenic epicenter and no association with a specific tooth.

Periphery and shape

• The periphery is ill defined early, reflecting active periosteal deposition, and becomes better corticated as lesions mature and remodel.
• The mandible shows smooth to lobulated external expansion with preserved overall bone outline, contrasting with the moth-eaten margins of aggressive destructive processes.[1]

Internal architecture

• The defining feature is dense cortical thickening from layered subperiosteal bone deposition, producing a sclerotic, expanded appearance of the ramus and angle.[1][3]
• Serial parallel layers of new bone may yield an onion-skin / lamellated pattern on the external cortex.[1]
• The underlying medullary cavity and existing cortex are generally maintained; frank lytic destruction is not a feature.[1]

Effects on adjacent structures

• Marked expansion widens the ramus and angle, with sclerosis of the surrounding bone.[3]
• Expansion can encroach on adjacent soft tissues and, with the overlying inflammatory swelling, accounts for the clinical facial mass.[3]
• Unlike malignant or infective processes, there is no cortical breach, sequestration, or soft-tissue invasion by bone.[1]

Growth pattern and extent

• Changes appear beneath the regions of soft-tissue swelling and evolve over weeks, with progressive thickening during the active phase followed by regression.[10]
• During healing, excess subperiosteal bone is resorbed through remodeling, and the mandible usually returns to near-normal contour, with residual change rarely detectable one to two years after the episode.[2][4]

Recognized variants and residua

• Residual deformity such as bowing, enlarged marrow cavities, or streaks of incompletely resorbed cortical remnants may persist in some cases, more typically in long bones than the mandible.[1]
• In the prenatal form, mandibular hyperostosis is nearly universal and is accompanied by symmetric hyperostosis of the skull base, ribs, scapulae, ilia, and long bones—a broader, symmetric pattern that should prompt consideration of Caffey dysplasia rather than classic ICH.[11]

The combination of fever, focal swelling, elevated inflammatory markers, and florid periosteal new bone overlaps substantially with infective, neoplastic, and traumatic processes; the self-limited course, multifocal distribution on a skeletal survey, and absence of bone destruction are the features that steer toward ICH.[1][4] The following alternatives are the highest-yield considerations for mandibular disease.

The highest-risk pitfall is mistaking mandibular ICH for osteomyelitis or malignancy and proceeding to biopsy or empiric surgery; a skeletal survey showing characteristic multifocal periostitis and recognition of the self-limited clinical tempo usually averts invasive intervention, and molecular testing of COL1A1 can confirm the diagnosis when it remains in doubt.[3][4]

Biopsy is seldom required and is reserved for atypical cases; histology is stage-dependent and nonspecific, which is itself a reason to favor clinical-radiographic diagnosis.[3][13]

• In the active inflammatory phase, there is subperiosteal new bone formation accompanied by a widened, fibrous (fibromatous) periosteum, resorption of the immediately underlying cortex, and an inflammatory infiltrate in the deeper periosteal layers.[10]
• Affected diaphyses and periosteum may be heavily vascularized with excess subperiosteal collagenous material.[10]
• In later or quiescent lesions, biopsy may show only hyperplasia of lamellar cortical bone without inflammation or subperiosteal hemorrhage, reflecting the remodeling phase.[13]

Radiologic-pathologic correlation

The layered subperiosteal bone seen radiographically corresponds to the periosteal new bone and fibrous periosteal expansion; the preserved deep architecture explains the absence of true destruction on imaging.[1][10]

Molecular findings

A heterozygous COL1A1 variant, c.3040C-to-T (p.Arg1014Cys; historically designated R836C), is identified in many familial and some prenatal cases, and a second substitution, p.Arg918Cys, has since been described, confirming allelic heterogeneity.[5][14] Both substitute arginine with cysteine in the triple-helical domain, producing abnormal disulfide-bonded α1(I) chains and altered collagen fibrils.[5][14] A pathogenic COL1A1 variant confirms the diagnosis, but because the variant is absent in many affected individuals, a negative result does not exclude it.[4][7][9]

Management is supportive, because ICH is self-limited and most infants recover fully without intervention.[3][4]

Workup and referral

• Establish the diagnosis with clinical findings plus a skeletal survey to document characteristic multifocal periostitis; radiography is the only imaging modality required.[1][4]
• Reserve advanced imaging for atypical presentations and avoid biopsy once a confident radiographic diagnosis is reached.[3][13]
• Consider molecular genetic testing (COL1A1) to confirm familial disease and inform counseling.[4]

Treatment

• Analgesics and antipyretics (commonly acetaminophen) control irritability and fever during episodes.[1][2]
• NSAIDs can relieve pain and inflammation; naproxen has been used to control symptoms and arrest progression in recurrent disease, consistent with a possible prostaglandin-related mechanism.[7][12]
• Short courses of corticosteroids are reserved for severe or recurrent symptomatic episodes.[3][4]
• No proven regimen prevents recurrence of hyperostosis.[2]
• Some COL1A1 p.Arg1014Cys carriers show Ehlers-Danlos-like joint laxity, skin hyperextensibility, and hernias, which are managed with standard measures.[2]

Prognosis, recurrence, and surveillance

• The outlook is excellent, with spontaneous resolution of swelling and radiographic remodeling of excess bone, typically by age two years and rarely detectable beyond one year after an episode.[2][4]
• Recurrence can occur, sometimes into adolescence, and the likelihood rises with onset after the first year; surveillance should be clinical, with repeat imaging only to characterize new episodes.[2][12]
• Lasting deformity or growth restriction is rare; fusion of adjacent affected bones is the main source of long-term morbidity, and some reports describe persistent skeletal and connective-tissue abnormalities into adulthood in familial disease.[4][8]