Hypohidrotic ectodermal dysplasia is a congenital disease characterized by the three principal features of dysplasia of the sweat glands, dysplasia of hair, and dysplasia of the teeth. Because it is discovered from abnormalities of the hair or teeth, the diagnosis is often missed in the neonatal period and made only after infancy. Herein, we report on two cases of infantile atrophic rhinitis diagnosed in infancy.

　Both cases presented with a foul smell from the nasal cavity from around 1 month after birth. Examination revealed a hard adherent crust in the nasal cavity, suggestive of atrophic rhinitis. We conducted a variety of tests based on the suspicion of ectodermal dysplasia, which led to an early diagnosis. The principal treatment is symptomatic treatment, but since nasal respiration plays an important role in growth and development during infancy, early intervention by an otorhinolaryngologist is very meaningful for improving the QOL. In general, otorhinolaryngologists would consider granulomatosis with polyangiitis, NK/T cell lymphoma, sequelae after radiation therapy, etc., in the differential diagnosis in patients presenting with atrophic rhinitis, however, in newborns or infants, it is important to bear in mind the possibility of ectodermal dysplasia.

　OK-432 is an antineoplastic drug, and it has been reported that in infants with lymphangioma, local infusion of the drug yields surgery-like effects. Herein, I report on the clinical outcomes of 12 patients of nead and neck cyst-related diseases who received OK-432 local infusion therapy at our institution between December 2013 and October 2015. The patient comprised 3 men and 9 women, ranging in age from 5 to 60 years old; there were eight cases of ranula, one cases of auricular hematoma, One case of parotid gland cyst, one case of lower lip cyst, and one case of a cyst on the side of the neck. In all cases, except the case with the cyst on the side of the neck, the lesion either reduced in size or altogether disappeared. Our results comfirm local infusion thrapy with OK-432 as an easy, minimally invasive and effective treatment for simple cystic diseases of the head and neck.

　Calcific tendinitis of the longus colli is characterized by calcium hydroxyapatite crystal deposition in the longus coli tendon, ant can manifest as sore throat, pain on swallowing, neck pain, trismus, and/or limitation of neck movements of sudden onset.

　We need to consider retropharyngeal abscess, which has a similar clinical course and a similar low-density area in the retropharyngeal space on computed tomographic (CT) images, in the differential diagnosis.

　We treated 2 cases of calcific tendinitis of the longus colli.

　In both the cases, in which we initially suspected retropharyngeal abscess, the correct diagnosis was made based on the following: 1) CT of the neck showed calcification of the soft tissues anterior to the atlas vertebra, and 2) the laboratory data showed relatively mild elevation of the serum C-reactive protein level and white blood cell count considering the severity of the clinical symptoms.

　We elected to treat the patients conservatively, which resulted in successful resolution of the symptoms in both.

　Retropharyngeal abscess carries a poor prognosis and could be fatal, whereas Calcific Tendinitis of The Longus Colli follows a benign course even without specific treatments.

　It is important to keep in mind this disease to avoid unnecessary invasive tests and treatments.