The condition is observed on the left side of the face about as often as on the right side. History
The disease was first described in 1825 by Caleb Hillier Parry (1755–1822), in a collection of his medical writings which were published posthumously by his son Charles Henry Parry (1779–1860). It was described a second time in 1846 by Moritz Heinrich Romberg (1795–1873) and Eduard Heinrich Henoch (1820–1910). German neurologist Albert Eulenburg (1840–1917) was the first to use the descriptive title "progressive hemifacial atrophy" in 1871. See also
Hemifacial microsomia
List of cutaneous conditions
Trigeminal trophic lesion

References
Further reading
Karim A, Laghmari M, Ibrahimy W, Essakali HN, Mohcine Z (October 2005). "[Neuroretinitis, Parry-Romberg syndrome, and scleroderma]". Journal Français dOphtalmologie (in French). 28 (8): 866–70. doi:10.1016/S0181-5512(05)81008-3. PMID 16249769. Lakhani PK, David TJ (February 1984). "Progressive hemifacial atrophy with scleroderma and ipsilateral limb wasting (Parry-Romberg syndrome)". Journal of the Royal Society of Medicine. 77 (2): 138–9. doi:10.1177/014107688407700215. PMC 1439690. PMID 6737396. Larner AJ, Bennison DP (September 1993). "Some observations on the aetiology of progressive hemifacial atrophy ("Parry-Romberg syndrome")". Journal of Neurology, Neurosurgery, and Psychiatry. 56 (9): 1035–6. doi:10.1136/jnnp.56.9.1035-a. PMC 489747. PMID 8410030. Miller MT, Spencer MA (1995). "Progressive hemifacial atrophy. A natural history study". Transactions of the American Ophthalmological Society. 93: 203–15, discussion 215–7. PMC 1312058. PMID 8719679. Pinheiro TP, Silva CC, Silveira CS, Botelho PC, Pinheiro MD, Pinheiro JJ (March 2006). "Progressive Hemifacial Atrophy--case report". Medicina Oral, Patologia Oral y Cirugia Bucal. 11 (2): E112-4. PMID 16505785. Zafarulla MY (July 1985). "Progressive hemifacial atrophy: a case report". The British Journal of Ophthalmology.
Parry–Romberg syndrome (PRS)  is a rare disease characterized by progressive shrinkage and degeneration of the tissues beneath the skin, usually on only one side of the face (hemifacial atrophy) but occasionally extending to other parts of the body. An autoimmune mechanism is suspected, and the syndrome may be a variant of localized scleroderma, but the precise cause and pathogenesis of this acquired disorder remains unknown. It has been reported in the literature as a possible consequence of sympathectomy. The syndrome has a higher prevalence in females and typically appears between 5 and 15 years of age. In addition to the connective tissue disease, the condition is sometimes accompanied by neurological, ocular and oral symptoms. The range and severity of associated symptoms and findings are highly variable. Signs and symptoms
Skin and connective tissues
Initial facial changes usually involve the area of the face covered by the temporal or buccinator muscles. The disease progressively spreads from the initial location, resulting in atrophy of the skin and its adnexa, as well as underlying subcutaneous structures such as connective tissue, (fat, fascia, cartilage, bones) and/or muscles of one side of the face. The mouth and nose are typically deviated towards the affected side of the face.The process may eventually extend to involve tissues between the nose and the upper corner of the lip, the upper jaw, the angle of the mouth, the area around the eye and brow, the ear, and/or the neck.