It is considered a disease of children with a peak incidence between 2-10 years of age. The disease is spread by person-to-person contact and risk factors include broken skin, overcrowding, and poor sanitation.
Clinical features can be broken down into early, latent, and late (tertiary) stages. Recurrent relapses may occur during the latent stage. After an incubation period of 3 weeks (9-90 days), it presents as a small papule that rapidly enlarges to a large papilloma. This primary papilloma (referred to as the mother yaw or frambesioma) is highly infected with spirochetes, very pruritic, and extremely infectious.
The mother yaw may persist for 3-6 months before spontaneous resolution (sometimes with scarring, sometimes without). Osteitis, periostitis, and dactylitis are rare correlating signs with early yaws. During this primary stage, the organism disseminates hematogenously and via the lymphatic system to give rise to secondary yaws. No neurologic manifestations or transplacental infections have been reported.
Nonsuppurative tender lymphadenitis, fever, and malaise may be associated with the eruption of secondary yaws. Periosteal and cartilaginous involvement may result in pain at these sites. Occasionally, after latent periods, recurrent lesions may present in moist body areas like the mouth, anus, and axillae. 10% of cases develop late stage yaws with necrotic destructive changes in the skin and gummatous changes in the bones.
Very late manifestations, if untreated, include bony and cartilaginous changes of the shins (saber shins) and nose (gangosa), as well as chronic bursitis.
A66.9 – Yaws, unspecified
70647001 – Yaws
- Endemic syphilis – Difficult to differentiate.
- Scabies – Mite prep positive.
- Tinea corporis – Potassium hydroxide (KOH) positive.
- Impetigo – Honey-crusted and occasionally bullous.
- Lichen planus – Striated scale.
- Psoriasis – Thickened scale.
- Tungiasis – Live flea present in nodules.
- Cutaneous leishmaniasis, Old World and New World – More inflammatory and crusted.
- Arthropod bite – Rapid onset and inflammatory.
- Sporotrichosis – Associated with trauma; lesions ascend the lymphatic chain.
- Atypical mycobacterial infection
- Tick granuloma
- Pinta – Usually slower growing.
- Cutaneous tuberculosis – Usually more suppurative.
- Cryptococcosis – Sometimes umbilicated.
- Juvenile xanthogranuloma – Yellowish in appearance.
- Basal cell carcinoma – Pearly rolled border; unlikely in children.
- Squamous cell carcinoma – More keratotic early; unlikely in children.