A66.3

Clinical Causes: Untreated or inadequately treated yaws infection, caused by the bacterium *Treponema pallidum pertenue*. Persistent skin irritation and chronic inflammatory response in the skin layers due to yaws. Repeated or prolonged exposure to the bacteria leading to skin changes over time.

Key Symptoms: Thickened, hardened areas of the skin on the palms and soles. Rough, scaly patches that may resemble calluses. Discoloration or darkening of the affected skin. Possibility of worm-eaten appearance, especially on the soles, indicating deep tissue involvement. Early signs include mild skin thickening, which can progress to more pronounced hyperkeratosis. Potential discomfort or pain in affected areas, especially if the skin cracks or becomes ulcerated.

Diagnosis Path: Diagnosis of hyperkeratosis of yaws involves a combination of clinical examination and medical history. Healthcare providers look for characteristic skin changes, particularly on the palms and soles, that correspond to yaws infection. Laboratory tests may include serological testing for treponemal antibodies or other specific tests to confirm the presence of *Treponema pallidum pertenue*. In some cases, skin biopsy or direct microscopy may be performed to examine tissue samples for signs of the bacteria. Accurate diagnosis is essential to differentiate from other causes of hyperkeratosis or similar skin lesions.

Treatment Protocols: Managing hyperkeratosis of yaws primarily involves treating the underlying yaws infection with appropriate antibiotics, such as benzathine penicillin or azithromycin, depending on the case and regional guidelines. Addressing skin thickening may involve topical treatments, including keratolytic agents, to soften and reduce hyperkeratosis. Preventative measures are also crucial, such as improving hygiene, reducing skin trauma, and controlling the spread of yaws through community health initiatives. Follow-up care includes monitoring for resolution of skin changes and preventing recurrence.