(See also Overview of Nail Disorders Overview of Nail Disorders A variety of disorders can affect nails, including deformities, infections of the nail, paronychia, and ingrown toenails. Nail changes may occur in many systemic conditions and genetic syndromes... read more .)
Causes of ingrown toenail include tight shoes, abnormal gait (eg, toe-walking), bulbous toe shape, excessive trimming of the nail plate, or congenital variations in nail contour (eg, congenital pincer nail deformity Pincer nail deformity Deformities are often considered together with dystrophies, but the two are slightly different; deformities are generally considered to be gross changes in nail shape, whereas dystrophies are... read more ). Sometimes an underlying osteochondroma Osteochondroma Benign bone tumors include benign giant cell tumors of bone, chondroblastomas, chondromyxoid fibromas, enchondromas, nonossifying fibromas, osteoblastomas, osteochondromas, and osteoid osteomas... read more is responsible, especially in the young. In the elderly, peripheral edema is a risk factor. Eventually, infection can occur along the nail margin (paronychia Acute Paronychia Paronychia is infection of the periungual tissues. Acute paronychia causes redness, warmth, and pain along the nail margin. Diagnosis is by inspection. Treatment is with antistaphylococcal antibiotics... read more ).
Redness, swelling, and pain may also suggest concurrent paronychia. In young patients (eg, < 20 years) with recurrent ingrown toenails, x-rays should be considered to exclude underlying osteochondroma Osteochondroma Benign bone tumors include benign giant cell tumors of bone, chondroblastomas, chondromyxoid fibromas, enchondromas, nonossifying fibromas, osteoblastomas, osteochondromas, and osteoid osteomas... read more . In the absence of an ingrown toenail, apparent granulation tissue around the toe suggests the possibility of amelanotic melanoma, which is often overlooked; biopsy is necessary.
In mild cases, inserting cotton between the ingrown nail plate and painful fold (using a thin toothpick) may provide immediate relief and, if continued, correct the problem. If the shoes are too tight, a larger toe box is indicated.
In most cases, however, particularly with paronychia, excision of part or occasionally all of the ingrown toenail after injecting a local anesthetic is the only effective treatment. After excision, a flexible tube can be used to separate the nail plate and painful fold and allow healing. If ingrown toenails recur, sodium hydroxide or phenol is applied to permanently destroy the nearby lateral nail matrix. Phenol should not be used if there is arterial insufficiency.