Case reports of morphea co-existing with other systemic autoimmune diseases such as primary biliary cirrhosis, vitiligo, and systemic lupus erythematosus lend support to morphea as an autoimmune disease.Borrelia burgdorferi infection may be relevant for the induction of a distinct autoimmune type of scleroderma; it may be called "Borrelia-associated early onset morphea" and is characterized by the combination of disease onset at younger age, infection with B. burgdorferi, and evident autoimmune phenomena as reflected by high-titer antinuclear antibodies. Diagnosis
Classification
Morphea–lichen sclerosus et atrophicus overlap is characterized by both lesions of morphea and lichen sclerosus et atrophicus, most commonly seen in women. : 171 
Generalized morphea is characterized by widespread indurated plaques and pigmentary changes, sometimes associated with muscle atrophy, but without visceral involvement. : 171 
Morphea profunda involves deep subcutaneous tissue, including fascia, and there is a clinical overlap with eosinophilic fasciitis, eosinophilia-myalgia syndrome, and the Spanish toxic oil syndrome. : 171   Morphea profunda shows little response to corticosteroids and tends to run a more chronic debilitating course. : 171 
Pansclerotic morphea is manifested by sclerosis of the dermis, panniculus, fascia, muscle, and at times, the bone, all causing disabling limitation of motion of joints. : 171 
Linear scleroderma is a type of localised scleroderma which is an autoimmune disease characterized by a line of thickened skin which can affect the bones and muscles underneath it. It most often occurs in the arms, legs, or forehead, and may occur in more than one area. It is also most likely to be on just one side of the body. Linear scleroderma generally first appears in young children.
Morphea is a form of scleroderma that involves isolated patches of hardened skin on the face, hands, and feet, or anywhere else on the body, with no internal organ involvement. : 130

Signs and symptoms
Morphea most often presents as macules or plaques a few centimeters in diameter, but also may occur as bands or in guttate lesions or nodules. : 171 Morphea is a thickening and hardening of the skin and subcutaneous tissues from excessive collagen deposition. Morphea includes specific conditions ranging from very small plaques only involving the skin to widespread disease causing functional and cosmetic deformities. Morphea discriminates from systemic sclerosis by its supposed lack of internal organ involvement. This classification scheme does not include the mixed form of morphea in which different morphologies of skin lesions are present in the same individual. Up to 15% of morphea patients may fall into this previously unrecognized category. Cause
Physicians and scientists do not know what causes morphea. Case reports and observational studies suggest there is a higher frequency of family history of autoimmune diseases in patients with morphea. Tests for autoantibodies associated with morphea have shown results in higher frequencies of anti-histone and anti-topoisomerase IIa antibodies.