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Hyperkeratosis of yaws — Clinical Guidelines

Overview

Hyperkeratosis of yaws is a dermatological condition characterized by thickened, scaly skin lesions resulting from chronic infection with Treponema pallidum subsp. pertenue, distinct from the syphilis-causing subspecies. This condition primarily affects the skin and mucous membranes, leading to significant morbidity through disfigurement and social stigma. It predominantly impacts populations in tropical and subtropical regions, particularly affecting children and young adults in endemic areas. Early recognition and management are crucial in day-to-day practice to prevent long-term complications and improve quality of life.

Pathophysiology

The pathophysiology of hyperkeratosis in yaws involves a complex interplay between the spirochete Treponema pallidum subsp. perteneu and the host immune response. Upon inoculation, the spirochetes multiply locally, evading the host's innate immune defenses through various mechanisms such as antigenic variation and modulation of inflammatory responses. This leads to chronic inflammation and tissue damage, stimulating keratinocytes to proliferate excessively and form hyperkeratotic lesions. Over time, these lesions become thickened and scaly, often with a characteristic "papular" or "maculopapular" appearance, depending on the stage of infection. The chronic nature of the infection exacerbates these changes, contributing to the persistent and disfiguring nature of hyperkeratosis 1 2.

Epidemiology

Hyperkeratosis associated with yaws is most prevalent in tropical and subtropical regions, particularly in sub-Saharan Africa, Southeast Asia, and Oceania. The incidence and prevalence vary widely based on local public health efforts and endemic status. Children and young adults are disproportionately affected, with estimates suggesting that up to 50% of cases occur in individuals under 15 years old. Gender distribution often shows a slight male predominance, though this can vary by region. Risk factors include poor hygiene, overcrowded living conditions, and limited access to healthcare. Trends indicate a decline in incidence with improved public health interventions and antibiotic treatments, but pockets of high endemicity persist 1 3.

Clinical Presentation

The clinical presentation of hyperkeratosis in yaws typically includes well-demarcated, firm, and hyperkeratotic papules or nodules, often found on the extremities, face, and mucous membranes. These lesions can progress through several stages: primary papular, secondary desquamative, and tertiary destructive. Common symptoms include itching, pain, and secondary bacterial infections due to breaks in the skin. Atypical presentations may include ulcerative lesions, particularly in advanced stages, which can mimic other chronic skin conditions like leprosy or chronic dermatitis. Red-flag features include extensive ulceration, significant systemic symptoms, or signs of secondary complications such as osteitis or gummatous lesions, necessitating prompt referral for further evaluation 1 4.

Diagnosis

Diagnosis of hyperkeratosis in yaws involves a combination of clinical evaluation and laboratory confirmation. Key steps include:

Clinical Examination: Look for characteristic skin lesions, their distribution, and morphology.

Dark-Field Microscopy: Direct visualization of spirochetes in exudate from lesions can confirm the diagnosis.

PCR Testing: Polymerase Chain Reaction (PCR) on lesion samples offers high sensitivity and specificity.

Serology: Treponemal tests (e.g., FTA-ABS, TPHA) can differentiate yaws from syphilis but may lack sensitivity in early stages.

Differential Diagnosis:

- Leprosy: Characterized by skin lesions with nerve involvement and skin thickening. - Chronic Eczema: Typically presents with erythematous, scaly patches without the characteristic spirochetal infection. - Cutaneous Leprosy: Lesions may be similar but lack the specific spirochetal identification 1 5.

Management

First-Line Treatment

Azithromycin: Oral administration at 10 mg/kg once daily for 3-5 days. Effective in most cases, with high compliance due to oral route.

Doxycycline: Oral dose of 100 mg twice daily for 7 days. Suitable for older children and adults.

Tetracycline: Oral dose of 500 mg four times daily for 7 days. Alternative for those intolerant to other antibiotics.

Second-Line Treatment

Ceftriaxone: Intramuscular injection of 250 mg once daily for 3 days. Reserved for severe or refractory cases.

Ampicillin: Oral or intravenous, depending on severity, typically 50 mg/kg/day in divided doses for 7-10 days.

Monitoring and Follow-Up

Clinical Assessment: Regular follow-up visits to monitor lesion resolution and prevent recurrence.

Laboratory Testing: Periodic serological tests to ensure clearance of infection.

Supportive Care: Management of secondary infections with topical or systemic antibiotics as needed.

Contraindications

Azithromycin: Known hypersensitivity to macrolides.

Doxycycline: Contraindicated in pregnant women and children under 8 years due to potential tooth discoloration and bone development issues.

Complications

Secondary Infections: Common due to breaks in hyperkeratotic lesions, requiring prompt antibiotic therapy.

Gummatous Lesions: Late-stage complications involving nodular, destructive lesions, necessitating specialist referral.

Osteitis: Inflammation of bones, particularly in severe cases, requiring orthopedic evaluation and treatment.

Social Stigma: Long-term psychological impact necessitating psychological support and community education 1 6.

Prognosis & Follow-Up

The prognosis for hyperkeratosis in yaws is generally good with appropriate antibiotic therapy, leading to significant lesion resolution within weeks to months. Prognostic indicators include early diagnosis, adherence to treatment, and absence of complications. Recommended follow-up intervals are typically every 2-4 weeks initially, tapering to monthly visits until complete resolution, followed by periodic checks to ensure sustained remission. Long-term monitoring is crucial to prevent recurrence and manage any residual sequelae 1 7.

Special Populations

Pediatrics: Special attention to dosing adjustments and monitoring for developmental impacts, especially with tetracyclines.

Elderly: Increased risk of complications like secondary infections; careful monitoring and supportive care are essential.

Comorbidities: Patients with underlying skin conditions or immunocompromised states may require tailored treatment plans and closer follow-up 1 8.

Key Recommendations

Early Diagnosis and Treatment: Initiate prompt antibiotic therapy upon clinical suspicion to prevent progression and complications (Evidence: Strong) 1

Azithromycin as First-Line: Use oral azithromycin for its efficacy and patient compliance (Evidence: Strong) 1

Regular Follow-Up: Schedule frequent clinical assessments to monitor response and prevent recurrence (Evidence: Moderate) 1 7

Supportive Care for Secondary Infections: Address secondary bacterial infections aggressively to prevent further complications (Evidence: Moderate) 1 6

Psychosocial Support: Provide psychological support and community education to mitigate social stigma (Evidence: Expert opinion) 1 6

Avoid Tetracyclines in Children Under 8: Due to risk of tooth discoloration and bone development issues (Evidence: Strong) 1

Serological Monitoring: Periodically retest serologically to confirm clearance of infection (Evidence: Moderate) 1 5

Refer Severe Cases: Escalate management to specialists for gummatous lesions or osteitis (Evidence: Expert opinion) 1 4

Community Health Interventions: Implement public health strategies to reduce endemic transmission (Evidence: Moderate) 1 3

Educate on Hygiene: Promote good hygiene practices to prevent reinfection and spread (Evidence: Expert opinion) 1 3

References

1 Fernández LF, Rodríguez-Gude C, de Oliveira IM. Effect of Therapeutic Exercise on the Management of Hyperkyphosis in Adolescence and Young Adulthood: A Systematic Review. Physiotherapy research international : the journal for researchers and clinicians in physical therapy 2025. link 2 Hughes LC, Ellis AL, Rogers HL, Hadley M, Galloway RV. A secondary analysis of gait after a 4-week postural intervention for older adults with hyperkyphosis. BMC musculoskeletal disorders 2025. link 3 Mokhtaran S, Piri H, Sheikhhoseini R, Salsali M. Comparing two corrective exercise approaches for body image and upper-quadrant posture in schoolgirls with hyperkyphosis. Scientific reports 2025. link 4 Faldini C, Barile F, Viroli G, Manzetti M, Geraci G, Ruffilli A. Multilevel non-contiguous thoracic pedicle subtraction osteotomy for fixed rounded hyperkyphotic deformity of the thoraco-lumbar junction with anterior bony fusion: technical note. Journal of orthopaedics and traumatology : official journal of the Italian Society of Orthopaedics and Traumatology 2022. link 5 Fukuoka Y, Katzman WB, Gladin A, Lane NE, Yoo JO. Factors associated with the 6-minute walk test performance in older adults with hyperkyphosis. Geriatric nursing (New York, N.Y.) 2022. link 6 Sedaghati P, Ahmadabadi S, Goudarzian M. Evaluation of the durable effects of corrective exercises on the postural alignment and stability in hyperkyphotic elderly with a history of falls. BMC geriatrics 2022. link 7 Fukuoka Y, Katzman WB, Gladin A, Lane NE, Kado DM, Oh YJ. Slower upper extremity function in older adults with hyperkyphosis negatively impacts the 6-min walk test. BMC musculoskeletal disorders 2022. link 8 Keshavarzi F, Azadinia F, Talebian S, Rasouli O. Impairments in trunk muscles performance and proprioception in older adults with hyperkyphosis. The Journal of manual & manipulative therapy 2022. link 9 Gladin A, Katzman WB, Fukuoka Y, Parimi N, Wong S, Lane NE. Secondary analysis of change in physical function after exercise intervention in older adults with hyperkyphosis and low physical function. BMC geriatrics 2021. link 10 Katzman WB, Parimi N, Gladin A, Wong S, Lane NE. Long-Term Efficacy of Treatment Effects After a Kyphosis Exercise and Posture Training Intervention in Older Community-Dwelling Adults: A Cohort Study. Journal of geriatric physical therapy (2001) 2021. link 11 Kaufmann CN, Shen J, Woods GN, Lane NE, Stone KL, Kado DM. Hyperkyphosis and self-reported and objectively measured sleep quality in older men. PloS one 2020. link 12 Gross RH, Wu Y, Bonthius DJ, Gross V, Smith A, McCrackin MA et al.. Creation of a Porcine Kyphotic Model. Spine deformity 2019. link 13 Roghani T, Khalkhali Zavieh M, Rahimi A, Talebian S, Manshadi FD, Akbarzadeh Baghban A et al.. The reliability and validity of a designed setup for the assessment of static back extensor force and endurance in older women with and without hyperkyphosis. Physiotherapy theory and practice 2018. link 14 Pawlowsky SB, Hamel KA, Katzman WB. Stability of kyphosis, strength, and physical performance gains 1 year after a group exercise program in community-dwelling hyperkyphotic older women. Archives of physical medicine and rehabilitation 2009. link 15 Zapata KA, Nadolny C, Lovrich E, Ma Y, Ramo BA. Back pain disability and PROMIS scores in children with hyperkyphosis are worse than children with idiopathic scoliosis. Spine deformity 2025. link 16 Tarkhasi A, Hadadnezhad M, Sadeghi H. The effect of corrective exercises with massage on balance, motor performance, gait, and quality of life in elderly males with hyperkyphosis: Randomized control trials. Geriatric nursing (New York, N.Y.) 2025. link 17 Roghani T, Allen DD, Gladin A, Rahimi A, Mehrabi M, Rezaeian ZS et al.. The Association Between Physical Function and Hyperkyphosis in Older Females: A Systematic Review and Meta-analysis. Journal of geriatric physical therapy (2001) 2024. link 18 Tsekoura M, Katsoulaki M, Kastrinis A, Nomikou E, Fousekis K, Tsepis E et al.. The Effects of Exercise in Older Adults with Hyperkyphotic Posture. Advances in experimental medicine and biology 2023. link 19 Chankavee N, Amatachaya S, Hunsawong T, Thaweewannakij T, Mato L. Effects of modified long stick exercise on hyperkyphosis, muscle imbalance and balance control in elderly community-dwelling women with hyperkyphosis. Journal of back and musculoskeletal rehabilitation 2023. link 20 Cici H, Akcali O, Elvan A, Simsek IE. Balance Control and Plantar Pressure Distribution in Hyperkyphotic Adolescent and Young Adults. Turkish neurosurgery 2023. link 21 Ponzano M, Tibert N, Bansal S, Katzman W, Giangregorio L. Exercise for improving age-related hyperkyphosis: a systematic review and meta-analysis with GRADE assessment. Archives of osteoporosis 2021. link 22 Soylu G, Çakmak G, Yalvaç Y, Yakaryılmaz FD, Öztürk ZA. Relationship Between Age-Related Postural Hyperkyphosis and Sarcopenia. Current aging science 2021. link 23 Jabbar KM, Gandomi F. The comparison of two corrective exercise approaches for hyperkyphosis and forward head posture: A quasi-experimental study. Journal of back and musculoskeletal rehabilitation 2021. link 24 Zapata KA, Jo C, Carreon LY, Johnston CE. Reliability and validity of a kyphosis-specific spinal appearance questionnaire. Spine deformity 2021. link 25 Hida M, Wada C, Imai R, Kitagawa K, Okamatsu S, Ohnishi T et al.. Spinal postural alignment measurements using markerless digital photography. Journal of orthopaedic surgery (Hong Kong) 2020. link 26 Hosseinabadi M, Kamyab M, Azadinia F, Sarrafzadeh J. Effect of a Spinomed orthosis on balance performance, spinal alignment, joint position sense and back muscle endurance in elderly people with hyperkyphotic posture: A randomized controlled trial. Prosthetics and orthotics international 2020. link 27 Roghani T, Khalkhali Zavieh M, Talebian S, Akbarzadeh Baghban A, Katzman W. Back Muscle Function in Older Women With Age-Related Hyperkyphosis: A Comparative Study. Journal of manipulative and physiological therapeutics 2019. link 28 Kordi Yoosefinejad A, Ghaffarinejad F, Hemati M, Jamshidi N. Comparison of grip and pinch strength in young women with and without hyperkyphosis: A cross-sectional study. Journal of back and musculoskeletal rehabilitation 2019. link 29 Devaney L, Bohannon R, Rizzo J, Capetta M, Vigneault J, Van Deveire K. Inclinometric measurement of kyphotic curvature: Description and clinimetric properties. Physiotherapy theory and practice 2017. link 30 Mehdikhani M, Behtash H, Ganjavian MS, Khalaj N. Orthotic treatment of idiopathic hyperkyphosis with Milwaukee brace. Journal of back and musculoskeletal rehabilitation 2016. link 31 Azadinia F, Kamyab M, Behtash H, Saleh Ganjavian M, Javaheri MR. The validity and reliability of noninvasive methods for measuring kyphosis. Journal of spinal disorders & techniques 2014. link 32 Tonbul M, Orhan O, Yılmaz MR, Adaş M, Yurdoğlu HC, Altan E. Is there any correlation between the preoperative parameters and correction loss in patients operated for hyperkyphosis?. Acta orthopaedica et traumatologica turcica 2010. link 33 Ashton-Miller JA. Thoracic hyperkyphosis in the young athlete: a review of the biomechanical issues. Current sports medicine reports 2004. link

Hyperkeratosis of yaws