1. General Considerations

   1. Post-clipping alopecia occurs after the hair is clipped typically close to the skin for any reason.
   2. The pathomechanism is unknown but it is speculated that skin temperature changes after clipping may induce most hair at the shaved area to enter telogen.
   3. The hair coat generally regrows after clipping within 3 to 4 months; therefore, failure to regrow hairs within this time period should be considered abnormal.
   4. No age or sex predilection has been reported.
   5. This condition may affect any breed but it has been noted more frequently in plush-coated (i.e. long thick coats) breeds.

2. Clinical signs

   1. Hairs will fail to regrow within 3 to 4 month post-clipping for any reason in otherwise healthy dogs.
   2. In some cases, complete hair regrowth will only be noted after 12 to 24 months post-clipping.
   3. The authors have noticed that it may take longer for hairs to regrow in the lumbar-sacral region but this has not been documented by controlled studies.

1. 3. Diagnosis

      1. The diagnosis is straightforward and based on the characteristic history and clinical presentation.
      2. It is important to rule out hypothyroidism, hyperadrenocorticism, or sex hormone-related alopecia for the cause of hair-growth delay in middle age to older dogs.
      3. Histopathology will show most hair follicles in telogen phase. Taking a biopsy sample from the opposite non-affected area will assure that the abnormality is only present in the shaved area.

   4. Treatment

      1. No treatment is needed because the hair coat should regrow within 1 year in most cases in otherwise healthy dogs.
      2. Melatonin can be tried in cases where owners are anxious for the hair to regrow but there are no studies to demonstrate that it is effective for this condition.
      3. A study showed that microneedling with or without platelet rich plasma could be a treatment option to induce faster hair regrowth in post-clipping alopecia. However, only four dogs were enrolled and a non-treated alopecic area was not included in the study design (see paper by Diamond et al for details). Therefore, more studies need to be done before this treatment modality can be adopted.

References

Cerundolo R. Canine post clipping alopecia. In: Mecklenburg L, Linek M, Tobin DJ, eds. Hair loss disorders in domestic animals. Ames, IA: Wiley-Blackwell, 2009; 163–164.

Diamond JC, Schick RO, Savage MY, et al. A small scale study to evaluate the efficacy of microneedling in the presence or absence of platelet rich plasma in the treatment of post-clipping alopecia in dogs. Vet Dermatol 2020; 31: 214–e45.

Miller WH, Griffin GE, Campbell KL. Muller & Kirk’s Small Animal Dermatology. 7th ed. St. Louis: Elsevier Inc., 2013; 564-566.

Muntener T, Schuepbach-Regula G, Frank L, et al. Canine noninflammatory alopecia: a comprehensive evaluation of common and distinguishing histological characteristics. Vet Dermatol  2012; 23: 206-e44. DOI: 10.1111/j.1365-3164.2012.01049.x

Scott DW, Miller WH. Retrospective record review of postclipping hair follicle arrest. Vet Dermatol 2012; 23: 248–249.

Stoll S, Dietlin C, Nett-Mettler CS. Microneedling as a successful treatment for alopecia x in two Pomeranian siblings. Vet Dermatol 2015; 26: 387–390. e88.

Welle M, Philippe U, Rüfenacht S, et al. MLPH genotype—melanin phenotype correlation in dilute dogs. J Hered 2009;100: S75–S79.