Congenital onychogryphosis

　　Congenital onychogryphosis is an autosomal dominant genetic disease. Type I is related to mutations in keratin 16 and 6a, and Type II is related to mutations in keratin 17 and 6b. This disease is a rare hereditary hyperkeratotic skin disease.

　　The main complications of congenital onychogryphosis include the following:

　　1. Paronychia

　　Paronychia is an inflammatory reaction involving the skin folds around the nail, manifested as acute or chronic suppurative, tender, and painful swelling of the perinail tissue, caused by paronychia abscesses.

　　2. Subungal abscess

　　Necrotic tissue caused by inflammation and other factors can form subungal abscesses.

　　3. Ingrown toenails

　　Ingrown toenails often occur in summer, with symptoms of millet-sized, deep vesicles between the toes, on the edge of the foot, and on the sole of the foot.

　　4. Necrosis at the distal ends of fingers and toes

　　The site of obstruction in congenital onychogryphosis varies, resulting in different clinical symptoms and signs. The clinical manifestations of acute obstruction and chronic obstruction are also different, but they can all cause ischemia, gangrene, or necrosis at the distal extremities.

　　The characteristic manifestations of type I congenital onychogryphosis are significantly thickened nails (toes), excessive palmoplantar keratosis, hyperhidrosis, and hyperkeratotic skin lesions in the elbows, knees, and buttocks. Nail changes appear after birth, but are more common within a few months after birth. Mucosal leukoplakia is more common in the tongue and mouth, occasionally involving the larynx, causing hoarseness. In addition, callosities can be seen on the plantar surface of the feet, and walking can lead to blisters. Callosities on the palm are only seen in manual workers. Other types of clinical manifestations are similar to type I, but type II is associated with fetal teeth and multiple sebaceous cysts; type III is associated with corneal leukoplakia; type IV has a later onset, and hyperpigmentation can be seen in the neck, waist, axilla, thigh, buttocks, and abdomen.

　　Currently effective methods for congenital onychogryphosis include health education, family history investigation, genetic counseling, malformation and risk prediction, biochemical testing, amniotic fluid and villus sampling, genetic testing, and cytogenetic analysis.

　　Patients with congenital onychogryphosis have significantly thickened nails (toes), excessive palmoplantar keratosis, and tissue pathology showing pigment incontinence and amyloid deposition. The disease can be diagnosed based on clinical manifestations, skin lesion characteristics, and characteristic histopathological features.

　　Patients with congenital onychogryphosis should eat foods rich in vitamin C and carbonated foods, and avoid eating high-calcium foods and foods that affect calcium deposition. The patient's diet should be light and easy to digest, with a high intake of vegetables and fruits, a reasonable diet, and attention to adequate nutrition.

　　In the treatment of congenital onychogryphosis, the excision of thick nails can only temporarily alleviate symptoms. Removing the nail matrix is not beneficial to the efficacy, but the excision of the nail matrix and nail bed is a simple and effective therapy. Keratolytic agents can be locally applied to keratotic lesions, such as lactic acid washes, salicylic acid, and urea preparations. Oral retinoids (isotretinoin) can clear keratotic papules and mucosal leukoplakia, but are ineffective for palmoplantar keratosis. Delayed-onset congenital onychogryphosis patients can try activetin treatment.