Congenital / Hereditary Alopecia


Congenital Alopecia/Hypotrichosis meaning the absence of hair or less hair than normal present a birth.

Hereditary Alopecia/Hypotrichosis meaning the absence of hair or less hair than normal that is passed along from one’s ancestry.

Alopecia areata meaning hair occurring in circumscribed patches or places.

Clinical Signs

Absence of hair beginning at birth or hypotrichosis meaning less than normal amount of hair beginning at birth. Also, may see Alopecia areata, patches of fur that comes and goes present since birth. May see curly whiskers.


Hereditary alopecia or hypotrichosis is what is most often seen by pet rat owners, as the Hairless Rat. Variations of hair loss can be seen in the different genetic makeup of these rats. Alopecia areata is also seen in some of these rats with recessive genes. They tend to show with sparse patches of hair on the head and rump.

In some cases, rats that are bred for hereditary hair loss have other congenital or hereditary abnormalities such as increased oxygen consumption, and higher metabolic rates. Some have shown to have decreased development of immune systems or show signs of having problems associated with lactation.


Photo Examples and Additional Genetic Information

  • Fig. 1: Photos of Hairless rat
  • Fig. 2: Basic Types of Genetic Alopecia in Rats
  • Fig. 3: Hairless Rat Care


Characteristic appearance.

Obtain History.


Treatment not required for hair loss itself. Treatment is for signs or symptoms associated with skin conditions or illness. Refer to Rat Health Guide Index for any conditions that may require treatment.

Nursing Care

  • For care of rats with congenital or hereditary hair loss, refer to Fig. 3 Hairless Rat Care, listed above.


  • Remains free of skin diseases
  • Remains free of skin injury
  • Optimum environment maintained
  • Healthy diet established


Links to


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